Driving GM’s Worst Transmission: The Roto-Hydramatic (“Slim Jim”)

Take a spin in this 1961 Oldsmobile F-85 Deluxe equipped with GM’s worst transmission, the Roto-Hydramatic.

[@joebutchko2223]

Your shift demonstration ride brings back this memory: years ago I was chatting with a SEPTA bus driver on his lunch break in Philly and he invited me to ride along for a turn. I had time, so off we went. Corner to corner folks getting on and off. I asked about the trans, an allison angle drive job- he said it was just a torque converter that locked up at 50 mph. " Here, I'll show you" and we took off. He had that 6v71Detroit screaming under the back seat, and it was a rough street, everything rattling, windows, doors, everything. Finally, the little detroit suddenly bogged down and a loud screech came from the transmission as the lock-up clutch tried to grab ahold of the engine. He yelled "SEE THERE IT IS!" then slammed on the brakes panic style and dove for the curb. Stopped right at the bus stop sign. Doors open. I turned around and the passengers looked terrified, and two women behind me, who didn't seem to know each other, were clutching each other. Quite a bus ride!

[@discerningmind]

Good lord! I can only imagine what would happen to that bus driver in the times we're living in now. Fired, news footage, law suites, public banishment...

[@trickyricky12147]

​@@discerningmindyep. Crazy times we're living in now. 👎

[@maineiacman]

Sounds like a fun ride. My school bus for middle school had a tiny little old lady that drove the bus using the gas pedal and brake pedals as on and off switches

[@duncanmacrae6384]

I has a friend with a 63 Starfire convertable. 394 4 barrel, Roto Hydramatic. Three rebuilds later, he said "as long as I drive it like a grand ma" it's fine. First time I get on it, it's back to the trans shop!

[@keithewilson9699]

Ouch

[@olds394]

Have a 63 Starfire and never been any problem at all. But is important not let morons wrench on them.

[@markreed171]

Time to upgrade the tranny.

[@Paul-y4d7i]

To own a car today with Problems today you're lucky to have cleaver people are able to get the car fixe

[@pete1342]

​@@olds394Why not, morons designed the thing, according to my old boss, who worked on many of them, lol. I did trans work exclusively for 20 years, got out of it back in '96, and have heard all the stories, but have never seen one.

[@jimgarofalo5479]

I have a couple of comments about both the engine and the transmission... First the engine. At the time when these were still on the road and in wide use, I was working in a Buick dealership full time and in an independent transmission shop nights and weekends. At the Buick dealership, we got quite a number of those V-8s in with leaking head gaskets. In most cases, the leaks were external in that they leaked coolant out of the sides of the head gaskets. Otherwise, the engines were quite reliable, and were not prone to putting rods through the side of the block like the infamous Buick 350 that was used in LeSabre and Skylark cars. As to the transmission, the biggest defect was really some poor engineering. For first gear, they used an internal fluid coupling instead of a torque converter. This had some pretty poor efficiency, which made for a soft engagement, but a really "slippy" first gear. When they shifted into second, the input shaft was coupled directly into a planetary gearset with full mechanical drive. At this time, for whatever reason, the fluid dumped out of the fluid coupling only to refill for third gear. Somebody must have really sat up nights figuring all of this out! One odd thing was that the input shaft was splined directly into a damper plate on the engine's flywheel, so removing one from the car was like a stick shift with cooler lines. Weird! I tried to repair one of them on my own, and never did get it to work right. I even took it to some of the old school guys for help, and even they couldn't find out what I did wrong. I finally just bought another transmission and ate the job. hope to never see another one of them!

[@fizzystream8868]

thanks for all the knowledge

[@theeoddments960]

Was the 350 known for throwing rods out of the block because of oiling issues or because of the quality of the rods? I owned a Buick 350 and I’ll attest to the block architecture being very strong and very well designed. Never knew they were known for throwing rods out of the blocks but I knew that they had famous oiling issues. Same as the 455.

[@jimgarofalo5479]

@@theeoddments960 Probably more for oiling issues. When I worked in a Buick dealership, we would have an average of 2 a week towed in with rods hanging out the sides of the block. It was quite a treat to get one of them to the upstairs shop up the ramp equivalent of a boxed staircase.

[@goratgo1970]

THANK YOU VERY MUCH Jim, I think you have answered my current "Buick bewilderment" in your explanation of the very odd - pressure plate looking flexplate bolted to the crank of my fully complete '62 Buick 215 (even the plug wires are still connected) I got for $250. My next issue is I have to figure out a proper flexplate to match to my narrow bellhousing ('91 Camaro V6) t-700r with small converter. Already have the adapter kit eng. to trans. Cheers.

[@buzzwaldron6195]

I never noticed much tranny peculiarity going from my '57 Olds 98 Starfire to '62 Olds Jetfire, maybe the turbocharged V8's big torque masked the tight shifts... '62 auto shifted at 4400 RPMs max... valve lifters pumped up by 4600 RPMs when manually shifting it with 50K miles on it... boost pressure on the underside of intake valves prolly contributed to lower RPMs pump up... Problem I did have with the '62 was the downshift valve started sticking in the valve body preventing being able to push the exhilarator pedal down... bought a '62 Buick special for $100 with 3 speed on the tree manual tranny and swapped that assembly in to replace the auto tranny... plus a floor shifter... kzbin.info/www/bejne/gKvaZopnp7eApck The TH350 auto tranny in my '75 Monte Carlo had imperceptively smooth shifts... The TH350 and TH400 are variations of the Chrysler TorqueFlite and GM even paid royalties to the same inventor... 200-4R/700R4 and 4L80 were 4th gear added overdrive versions of them...

[@jeffsmith846]

What Mark said about other drivers is spot on. I hate driving my 62 Lincoln for the exact reasons that he gave. I leave space between me and the car in front in case they stop quickly. 9 times out of 10 some a@@wipe on their cell phone driving their SUV will cut in front of me. This happens in six lane traffic and also on local artery streets. Part of the problem is none of the drivers under 40 years old ever had drivers ed. Get off my lawn! Lol

[@circleinforthecube5170]

i think a big part of traffic stems from the issue of suburban sprawl

[@kem0n0.kokomo]

@@circleinforthecube5170 Yea, that's definitely a talking point you took from idiotic youtubers lmao

[@engineerisengihere44]

Big cause of people who dont know how to drive is technology. The tech in cars these days basically allows people to ignore half the road and get away with it. In my 1992 taurus even people cut in front of me and swerve around and tailgate me all the time (even if im going 80+ on the expressway). They just dont understand that their life and others' are at risk every time they get behind the wheel. Maybe I should become a DMV drivers license tester so I can fail all the people who don't deserve to pass 😂

[@billiebobbienorton2556]

It would have been nice if there WAS LESS TALKING so we could actually hear the shifting......

[@Sedan57Chevy]

I could live with the rough shifts, but the unreliability is such a detriment to an entire generation of otherwise excellent GM cars. There was a 63 Catalina for sale near me recently, absolutely gorgeous, but I don't have the confidence to live with a slim Jim in today's world of difficulty trying to get parts and not pay a ridiculous fortune for them. Love the brochures! Automobile marketing back in those days is almost as much fun as the cars themselves.

[@duncanmacrae6384]

Yup, same here, love the Pontiac and Olds body styles 62-64 but not the transmissions. Manual trans cars of that era are rare also.

[@lsswappedcessna]

If I were to get a car with a slim jim, original or not I'd feel bad for letting it sit due to their questionable reliability, so I'd probably end up trying to find a Jetaway or Powerglide to swap into it, or maybe a 700r4 if they make a BOP bell housing adapter for them.

[@mdogg1604]

Rod & Custom years ago mentioned a '63 Pontiac where the owner swapped to a GM overdrive, getting 23 mpg on the highway.

[@lsswappedcessna]

@@mdogg1604 Damn, that's pretty impressive. By OD do you mean something like a 700R4/4L60 where gear 4 is basically your OD, or a manual with OD? If it's getting 23 with an auto that's pretty insane.

[@mdogg1604]

It was either the 200 or 700 automatic OD. I think some custom adapter/machining was necessary. I believe the 23 mpg claim. I still get over 25 mpg on the interstate with my '90 Cad DeVille. @@lsswappedcessna

[@steveflor9942]

It sounds like there are some straight cut planetary gears. Lovvve the pod IP. Such a cool car. Makes me sad they weren't more of a success. Fascinating. Thanks for Showcasing.

[@CanizaM]

The reason for the harsh 1-2 shift on these, and also the 2-3 in the earlier original 4-speed Hydramatic, is that it has to simultaneously engage and disengage two elements. The 4-speed used two 2-speed gearsets in a row, each providing either direct or reduction, so the 2-3 shift there was one gearset going from direct back into reduction while the other goes into direct. If one goes into reduction before the other goes into direct, 2-3 becomes more like a 2-1-3 and the engine flares up in the middle, while if the other goes into direct first, it becomes a 2-4-3 and briefly bogs down. However, since that transmission used regular clutches and bands, that simultaneous shift could still be somewhat accurately timed. Some modern transmissions do have 2-element shifts just with clutches and bands, and the shifts are electronically timed with a computer, but they still give harsher shifts than ones that have exclusively single-element shifts. On the Roto, one of the elements being controlled is actually the torque converter which gets emptied and filled with fluid to act as a clutch. In first, it's filled, and then on the 1-2 shift it has to empty and the front clutch apply simultaneously. However, emptying the torque converter of fluid obviously takes a lot longer than releasing a clutch, and therein lies the problem: both the clutch and converter filled gives third gear (direct), and it'll always take longer to empty the converter than apply the front clutch. Furthermore, emptying and filling the converter is dependent on the viscosity (related to temperature) of the fluid, so it's not very consistent. Thus during the 1-2 shift, while the converter is emptying but the front clutch has applied, the transmission is actually in 3, so 1-2 is always like a 1-3-2 shift. This is further harshened by the fact that 2 doesn't involve any transfer of power through a fluid but is a direct mechanical connection from the engine through the gearset to the output. Then the 2-3 shift is very soft since it only has to fill the converter again. Looking at the hydraulic schematics, it seems they did try to soften the 1-2 by slipping the front clutch with a pretty complex system of valves for the timing, but that only leads to higher wear and shorter service life. The TH400 that replaced it and became a GM standard was and is highly regarded as one of the best in reliability and shift quality; all of its shifts are single-element. tl;dr: Rotos always shift 1-2 roughly because they have to do two things at the same time or else end up in 3rd briefly, but one of those two things (the converter emptying) will always be slower than the other. Trying to slow the other thing down (the clutch applying) makes it wear out faster.

[@bigstuff52]

very nice tutorial...Thank you..

[@danesworkshop]

Excellent explanation!

[@garyfrancis6193]

Oh.

[@jimgarofalo5479]

Sorry to have to correct you, but that unit in the middle of the transmission is NOT a torque converter. It is a fluid coupling. A torque converter needs to have a STATOR to direct oil flow. In this case, there is NO STATOR, thus making it a fluid coupling. Just two elements - pump and turbine. No stator.

[@CanizaM]

@@jimgarofalo5479 there''s a stator, but it's not on a one-way clutch like a typical torque converter. It's mounted to the output shaft. Weird design choice, but nonetheless, it still multiplies torque from a standstill so I would consider it a torque converter. Oldsmobile marketed it as the "accel-a-rotor", and you can see at 00:45 in the lower right corner. There's a disassembly video here on KZbin (just search for it) where at 15:50 you can clearly see the stator being pulled out. The original Hydramatic and the Controlled Coupling use true 2-element fluid couplings.

[@phillipleeds296]

That V8 was ultimately developed by Leyland Australia into a 4.4 litre version (taller deck for longer stroke) for the P76 sedan in the early 1970s.

[@buzzwaldron6195]

That engine eventually got out to 5.2L/318"... later all iron version out to 5.7L/350"...

[@DoudD]

Good video! I've subscribed. I learned a bit about the Roto-hydramtatic. Never knew there were two versions, never knew the senior compacts used it. However, it was very hard to hear/sense what the transmission was doing thanks to ten minutes of non-stop conversation about how smooth the ride was ! 🙂

[@RareClassicCars]

Ha. Sorry!

[@GeelongVic7140]

Adam, every session with Mark is a treat. The F85 drive was a revelation, but then what was GM thinking when it released the rapidly proven to be unreliable Sim-Jim Roto Hydra-Matic to the public?

[@RareClassicCars]

Not quite sure. I’m surprised it passed durability tests.

[@bobwilson758]

Couldn’t have passed anything ! Manual transmission only - for that model !

[@kellismith4329]

@denniswilson8013 that makes no sense, the powerglide transmission they used in the rest of the cars was amazing albiet only a 2 speed - racers still use them to this day

[@nlpnt]

@@kellismith4329 FWIU automatic Pontiac Tempests had Powerglide because they were using rear-mounted transmissions so shared them with the Corvair.

[@PearComputingDevices]

It's litterally a grandma transmission because this car was aimed at older buyers, it was also aimed at being an economical option next to the manual transmission something grandmas bu 1961 didn't want. I think it was even cheaper to make than a powerglide two speed. But I would still take that transmission any day over this. My dad and I seen them all the time for sale at swap meets for that reason. Most would take the two speed over this too. But from a marketing perspective to an older person more speeds must mean smoother, superior ride an unfortunately not so much. I would call it one of GM's worst. There might be others one could name, the slim-jim was one of the wost I've seen.

[@Dac54]

Listening to the upshift from 1st to 2nd brings back memories of a buddy of mine's 1964 Olds Dynamic 88. Since the car had a 394 cid V8, it moved quite well, but that upshift from 1st to 2nd is unforgettable. Oh, and it had an enormous trunk, ice-cold factory air conditioning, and that dashboard mounted sensor that automatically dimmed the high beams.

[@adotintheshark4848]

I had a '60 Pontiac with the older HydraMatic. It worked without breaking, but its shift from 2nd to 3rd was a big drop in RPm. They were like that.

[@fmphotooffice5513]

Auto hibeam... heehee... Where I am it's even easier. Half the drivers don't bother turning them off. The other half have those new lights that blind you anyway... I hate driving at night now.

[@rogerdodrill4733]

@@adotintheshark4848 had a few hydramatic Cadillacs 1/2 shift was fast, usually before you cleared intersection 2/3 was big jump 3/4 was close again like 1/2

[@fireballfireball1067]

I had one of these transmissions in my Australian 1964 EH Holden . I loved it, but they did not last too long, maybe 100,000 miles with the small 6 cylinder engines. I had a Australian Trimatic (turbo hydra 180 to you) fitted in 1988, still in there 35 years later. but a big drop in fuel economy. 24-25 mpg down to 19-20 mpg

[@cdstoc]

The station wagon looks much like the Corvair wagon. I wish I still had the 1961 Corvair Lakewood wagon that I used to drive around in the late 1970ʻs. It was a really nice size. My dad had modified the engine (a 1964 Monza engine, base HP 110 but ours put out about 180), put stiffer springs and shocks on it, and it had the 4-speed manual (no PowerGlide, yay!). It was a lot of fun.

[@nunyabidniz2868]

That 2-spd PowerGlide GM put in the Corvairs was a "better idea" worthy of Ford... You were lucky to have one with one of the (rare) 4 spd manuals! 🤑

[@rogerdodrill4733]

​@@nunyabidniz2868I've had 3 early corvairs they were all sticks& reliable.I've heard they were strong as behind v8. With v8 swap they would still hold up

[@joshuagibson2520]

Brochures, literature, and repair manuals are awesome. Please keep inclluding that on occasion.

[@bretfisher7286]

That drive was actually sort of fun, to me! The idiosyncrasies of these ancient classics are really fun. But I'd say that if the Roto-Hydra-matic was paired with a four-cylinder, it might actually stall it! 🤣

[@guglielmo64]

Horrible transmission. It died on my grandfather's great '62 Dynamic 88. This f-85 is very nice looking car. It's a shame GM had to screw-up the trans.

[@AlexanderWaylon]

Nice follow up! Have a good day!

[@jerrystaley1563]

Adam, thanks again for your 2nd video on the 1961 F-85. During my junior year (1963-1964) in high school, I had a similar 1962 4-door standard F-85 - white with blue interior, auto and factory a/c. Showing off to my buddies, I backed out of a driveway and slammed the gearshift into Drive whilst still rolling backwards. An incredible clunking noise eminating from beneath the floorboards ensued. After much worry, I took it to our only Olds-Cadillac dealer for an inspection. A workorder with the notation "auto needs a rebuild" and a $214 quote shook my little 17-year-old world. As my part time job as checker at a grocery store earned an incredible $1.15 per hour, I didn't know where to turn. A customer suggested that her auto mechanic husband have a look. A day later, Ray test drove it, pulled to the side of the road, lifted the hood, asked me to give it a little gas while holding the brake. From beneath the hood, I could see the engine raise up as torque was applied. Long story short, he replaced the engine.mounts and the noises went away. Small shop mechanics are a LOT better than certain dealerships. The only thing that I miss from that little F-85 was the "Ka-WOO" moan from that 2-bbl carb under hard acceleration!

[@weegeemike]

Neat car. New cars will never compete with the ride of the older American cars. Back when comfort and cruising was prioritized over the rough, tight, sporty feel found in todays cars. Great video.

[@jnightingale1918]

What a great demonstration of the Roto-Hydramatic transmission. A beautiful car indeed. The brochures are a great resource, thanks for sharing.

[@robfmas]

All of those sounds of the transmission shifting, the mechanical sounds, make you love these cars from the sixties. Glad to see this model in such great shape.

[@DSP1968]

The sound of the transmission brings back memories! I really like the script on the dash of this car. It was also interesting to see that it was not equipped with a radio. And the interior/dash looks as great as the exterior. P.S. They used to measure trunk capacity difrerntly than they do today.

[@jetsons101]

Back in the day the trunk was measured by how many high school kids could squeeze in the trunk for a Drive-In Movie........ lol

[@tracygeddes5867]

Watching the man talking Bending those valuable brochures and stabbing them was almost too much to take!

[@8900feet]

Well, if you two would quit talking I could hear it shift!

[@jetsons101]

Adam not to get off subject but that blue sky and clouds with the trees (6:57) is really a sight to see. Now back to the car.....

[@stevevogelman3360]

That’s a really nice looking car. It’s a shame that their so rare. I’ve never seen one in the wild. The wagon was very cool. Thanks Adam.

[@Knaeckebrotsaege]

What exactly is the point of a demo video with such an absurdly heavy noise filter over the entire audio that you can't really hear anything of what it's doing?! smfh

[@FedkaSlovanich]

sounds like they are doing a voice over

[@henryfam58]

Looking at the suspension coil spring placement surely has helped with that soft ride.

[@Greatdome99]

Not geometry, just spring rate (thinner coil wires, more windings).

[@jsd795]

So in other words it is a pretty darn good car with an awful transmission. Kind of a shame really.

[@michaeltolomei6623]

Man that alarm clock looking gauge and shelf dash is different for sure. I'm not sure about that styling, definitely unique but it kinda gave the over all inside a disposable, very basic feel, as opposed to Old's prior dashes, and GM as a whole, and what was to come through the decade for that matter. On the one hand I guess you got a nice shelf for snacks at the drive in.

[@NorthernChev]

I guess we can’t all be TH400s.

[@Danger_mouse]

It would have been great to hear the engine and the shifts on the test drive. I bailed out after a few minutes of the video as you both kept talking over top of the engine. Kinda pointless, as your audience can't feel the car or see the shifts, we can only hear.

[@paulypooper2]

One of my friends in high school father had the 1961 I believe Buick Skylark with the 215 aluminum block V8 and it was a very peppy car and we were hoping to one day put the engine into a Vega or Pinto ..

[@rogerdodrill4733]

Wave a 215 in my vega now. no heavier than vega 4. Stock springs work well

[@Primus54]

These “Senior Compacts” performed much, much better with manual transmissions.

[@MisterMikeTexas]

Could you get a factory 4 speed?

[@Primus54]

@@MisterMikeTexas No… transmission options on the 1961 Tempest were a 3-speed manual or 2-speed automatic. A 4-speed manual became available in 1962 and beyond.

[@captain150]

Though slow and unreliable, I gotta say the small whine sound it makes is pretty cool.

[@williamdavis8161]

My 1st car was a Pontiac with this trans. Had it "rebuilt" & still had problems. Only good thing about it, it motivated me to trade it for low mileage '67 Impala convertible.

[@MrSloika]

"...create some kind of moment of menace or threat." Yup, I've definitely noticed this while driving old cars...the oldest cars I've driven were from the 60s. Operating an old car today, even if it can easily keep up with traffic, like a mid-60s V8 Mustang, seems to really enrage some people. I could understand if I were driving a Model T on the NJ Turnpike, but I had one guy lose his mind when he saw me driving a 1965 Ford Falcon V8. I was in right lane of a two lane road, doing the speed limit (45 mph) and was not in his way at all.

[@rogerdodrill4733]

Some people become dicks when behind wheel, almost like jeckle & hyde

[@solemandd67]

That's sad. Seeing a classic car being driven always makes me smile. When I drive mine, like most owners, I drive it with self respect, safety and appreciation. Never to be a nuisance on the road. People have become more entitled cruel especially on freeways. Sometimes it makes me take a longer route to avoid hot heads.

[@MrSloika]

@@solemandd67 Go back and read my original post. I wasn't in this guy's way. I didn't cut him off, I wasn't blocking his way. He saw me driving an old car and then got in front of me and repeatedly brake checked me. As far as I can tell he targeted me for no other reason than I was driving an old car.

[@rogerdodrill4733]

@@MrSloika jealous people try to damage something they don't have without reason

[@Carefree6714]

One of my favorite GM bodies AND a groovy mid century neighborhood!

[@stevevarholy2011]

The 1-2 shift kinda reminds me of the TH125 in my 1982 Citation X-11. The H.O. V6 is so torquey, if you are laying on it, the 1-2 shift is very apparent and the torque steer will grab the wheel if you are not expecting it. The 2-3 shift is always imperceptable unless you are at wide open throttle. Never been an 1960's Oldsmobile fan, but this F85 has really sharp styling.

[@dansmusic5749]

I had always wondered about the shifting order on a Hydra-Matic quadrant. I heard on a video here on KZbin that was done deliberately to take advantage of the close proximity of Low and Reverse to facilitate rocking the car out of snow, sand or mud. The roads were not as good when the Hydra-Matic was developed so practicality demanded this feature. Also, I have learned that the Hydra-Matic had push-to-start capability. Not too many automatics are capable of this. I do not know if the Slim Jim had this feature.

[@enragedgrandpa2889]

Any older auto with a rear pump can be push started, but usually around 30ish mph. Likely the same for this one, to get the fluid coupler spinning fast enough to spin the engine you would need to go fairly fast.

[@tedcowart3647]

Nice car! I had a 61 Cutlass with the 215 4 barrel engine and the Roto transmission and I put 100k hard miles on it myself. It had over 100k on it when I bought it for $200 back in the 80's. My transmission shifted very well and was not nearly as loud as yours. If you just had yours rebuilt you need to take it back. It's not right. Also mine had a 120 mph speedo and I think I've still got the factory AM radio around somewhere.

[@VAspeed3]

Thanks for mentioning the speedo! My father bought a new '62 Cutlass with the 4bbl and 4 on the floor. When I saw the only100MPH speedo on this car I knew it was different from the car I grew up with. Ours was definitely 120mph.

[@TaylorZ2]

Did these cars have worse reliability than the Tempest? The resemblance to Tempest is incredible. Great video as usual.

[@nlpnt]

I just mentioned it in a response further up but the Tempest used a front engine/rear transmission setup so they shared the Corvair Powerglide (and manual 'boxes).

[@buzzwaldron6195]

Chevy Corvair/Monza/Olds F85/Cutlass/Buick Special/Skylark/Pontiac Tempest/Lemans all same body platform... Pontiac/John DeLorean didn't seem to want anything to do with that rough running early Buick V6, though...

[@singlesideman]

Boggy? Weird. Slow or delayed, sure, but boggy?

[@brygram]

Isn't second gear sort of a direct drive? That's why it is jerky in second. I had several 62 Olds Starfires, which I believe have the same transmission? It would seem to me that the transmission shop should be able to adjust the shift rod so that the shifts happen later (at higher RPMs)? Loved gear second in mine...as a direct gear the acceleration was epic...just get off the line, let it shift into second gear, then nail it...second gear would last until 90mph.

[@Slimjim260]

Nice neighborhood!

[@markbehr88]

Thanks Adam and Mark. That was insightful and enjoyable.

[@troynov1965]

The early Buick autos were pretty bad as well.

[@rightlanehog3151]

Adam, After careful deliberation, I will choose the Radio City Rockettes over the Oldsmobile Rockette engine. 😉

[@blakeneysanders4264]

I think the shocks back then were hydraulic and not gas, which is a problem if you are not aware of it. Check with Viking Shock (not sure on the last part of the name but Viking is correct) also I think QA1 makes hydraulic shocks. Thanks for the video.

[@waltcraig8098]

Regarding the old shift quadrant, NDLR with or without P was standard. Legend has it the change to PRNDL was because someone got into their new car with an automatic VS the old “three on the tree”. That person, out of habit, pulled the shift lever down First which was, of course, not First but Reverse. Supposedly the driver ran over and killed someone in a parking lot. Don’t know if there is any truth to that story, but it seems reasonable.

[@williamsiefert5144]

Unified shift patterns, like left side shifters on motorcycles are mandated by the feds. I still remember jumping off my Honda onto an old TR6 Triumph and doing some interesting braking and shifting. (I was a motorcycle tech back in the day.) Made life interesting.

[@jakespeed63]

After owning and servicing 6, 1964 Oldsmobile, FS models, I opted to swap in a TH400, behind the 394, of my ‘64 98 Coupe. What a major difference it made. Bought my first one, while attending tech college in Lima Ohio, circa 1983. My automatic transmission instructor, had been a GM line tech, when these were new. When asked if I could fix Slim Jim, he told me, “Son, they were junk then and they are junk now” Thanks for sharing this delightful video. Love the car.

[@johnelliott7375]

Trying to hear the boggy second over the voices 😊

[@DRNEGOLICIS]

My 94 4l80e makes that sound

[@pierrevoyemant7137]

Our 62 Buick Special had the two speed Dynaflow and the drive ability and acceleration was impressive. I think it had a lock up torque converter. It also had needle bearing a-arm bushings. Was that an unusual feature?Thanks for talking about these forgotten cars.

[@MisterMikeTexas]

What space capsule did that speedometer dash pod come off of? Good video, nice looking car.

[@tombrown1898]

I learned to drive on our 1963 Olds Super 88, with the "Ultra High Compression" Rocket V8, and Roto Hydramatic. The drive brought back (bad) memories. My best friend's mother had a 1963 F-85, which she bought used. The transmission failed not more than a year after she bought the car. Her replacement for the F-85 was a 1964 Dynamic 88.... Same boggy transmission, but it didn't crap out. Great to see Marc again!

[@James-j4l2y]

Our local Pontiac dealer shop told the customers. "The transmission is junk. I'm ordering a real Hydra-matic in. It will be day longer but you'll have no more trouble."

[@bobbyheffley4955]

Catalina and Grand Prix

[@DejaView]

@@bobbyheffley4955 Hadn't thought about it before but since the long wheelbase Bonneville & Star Chief had the (real) "Super Hydramatic" I'll bet there were a lot of Pontiac dealers that, perhaps for a price, switched over the Catalinas & Grand Prixs from the Roto to the Super. I wonder if they had to modify the driveshaft? It probably had to be shortened. I wonder if the Olds dealers did it too or if the floor pans in the Olds didn't allow for the larger trans. I know in the early '60s they were quite proud of how they had slimmed down the transmission hump....

[@bobbyheffley4955]

@DejaView this is the main reason Pontiac and Oldsmobile adopted the Turbo-Hydramatic in the 1965 model year

[@kayeninetwo3585]

I had the Roto Hydromatic transmission rebuilt in my '63 Olds 88 coupe, and it functioned fine after that, but it still had the odd shift trait. Some people described it as having a "bumped from behind" kind of feel, and I think that's a fairly accurate description of the sensation. Once you know that's just the way the trans operates, it's not a big deal and you get used to it. On vintage cars that don't get used much or subjected to heavy duty use, such a transmission is probably fine (if in good condition) but if you have ideas of hauling an equally vintage Airstream trailer around with your old car...you may want to rethink your plans.

[@randywelch55]

I owned a 1962 Buick special in mint condition, but could not find anyone to fix or rebuild the crappy transmission to stay working.. Eventually sold the car for nothing. a crying shame as the car was awesome and drove like a cadillac

[@Paramount531]

I love small wagons and these are great ones. I have seen many of these over the years, a grade school classmate of mine's family had the Olds version. They got rid of it in 1968 and replaced it with a very nice blue Chrysler Newport. I'm sure their fuel bill went up pretty dramatically after that.

[@92nbush]

To think automatic transmissions were really only around for 10yrs when this was probably planned and developed/ tested in the late 50s. Not to mention average comfortable cruising speed was 35-45 for most people and with some highways 55-65. That's probably what it's designed to do get to 35‐45 quickly then lockup for efficiency.

[@eriksmith6873]

I am so blown away to see people chattering about the tranny I have lived with for 37 years. I have a '63 Catalina convertible on my driveway at this very moment. Pontiac center consoles in '63 and '64 had a vacuum pressure gauge that makes it easy to determine what speed offers the greatest fuel efficiency. What I found, after years of experimentation, is that the car moves at maximum efficiency on the highway at precisely 52 mph. At that speed, in the days of the 55mph speed limit, I drove from Seattle to LA and got 21.5 mpg. At 70 mph, it's more like 14 mpg.

[@johnwinter9722]

Ah, the infamous Slim Jim. Yes, I had one. A baby blue '63 Catalina two door hard top. In many ways a very nice clean seven year old car when I bought it. Mine had a new transmission at 70k miles. Motor was very strong and overall the car was trouble free for the year I owned it. My grandfather bought it from me as it had power steering and brakes and was fresher than his rusty but trusty '60 Belair. He had it for five or six years. As for the Slim Jim, every time it shifted into 2nd gear I cringed. Would it make it? Would it fail this time? Anyone's guess. My dad, who in those years drove 25k miles or more every year, had a '64 Safari that he bought new when I was 10. I really don't remember any issues with drivability or reliability, and he drove the pants off that wagon including hunting and fishing trips, a vacation trip from MN to CA, and using it as a wagon was meant to be used. He traded it in after 75,000 miles or so and said it had some funny noises coming from the transmission on his way to the dealership. Probably ready to fail? Good memories of the cars, but that tranny was something else.

[@sharkinstx]

These cars also used a two-piece driveshaft with a double Cardan joint in the center, which helped keep the tunnel smaller. Somewhere I have one of the little brochures like the one featured in the video. It was inside a Popular Mechanics magazine that I bought at a used book shop when I was a kid (50+ years ago). I can re seeing these cars when I was a kid in the ‘60s (who could forget that dash?), but these disappeared quickly, headed to an early demise, thanks to the Slim Jim.

[@jw77019]

Always been obsessed with these various GM transmissions. As I recall Olds and Pontiac used S instead of 2. Cadillac had drive with 2 positions. On the 1964 and newer the right position was equivalent of 2. On the older ones the right position locked out 4th gear. I never drove or even saw the original hydramatic.

[@bobbyheffley4955]

S=super

[@MarinCipollina]

@@bobbyheffley4955 I remember asking my father what the 'S' meant on our new 1965 Grand Prix, and he said it meant 'Super'.

[@rogerdodrill4733]

Cads from 59 /63 had em, then got turbo 400

[@jetsons101]

What a great car, I bet a car like that would go forever is it was a manual shift. Wish you had segment of taking the air cleaner off the carb to see how it cooled the carb, I have never seen a air cleaner like that. Thanks for your time, work and posting......

[@scottsullivan1464]

Is this transmission basically a Powerglide with a first gear? Powerglides were 1.73: 1 and 1:1

[@DejaView]

@scottsullivan1464 No, nothing even close to a Powerglide. Best I can describe, it was a hacked up scaled down derivative of the 2nd generation (1956) "dual coupling" Hydra-Matic. Original H/Ms used a single fluid coupling located up front where the torque converter would be in typical automatics. The fluid coupling acted as a "clutch" to get the car moving but had no ability to multiply power. To assist the take-off they used multiple planetary gearset to achieve 4 forward speeds. They were not very smooth shifting however. In '56 they were redesigned with a 2nd internal fluid coupling (you can imagine these transmissions were not small or lightweight). They actually created smoother shifts by draining the fluid (no engagement when empty) & refilling the 2nd coupling. Since it took a moment for the coupling to drain or to be refilled there was no distinct "feel" to when the next gear engaged. Way too complicated but it worked. Crazy, huh. For the new compacts like the F-85 they needed something smaller & lighter & somehow figured they could eliminate the front coupling, have the small internal one do, basically all the work. They also eliminated the extremely low 1st gear & had only 3 speeds. They still did not use a true torque converter but created a kind of "hybrid" fluid coupling by adding what the brochure called the Accel-a-rotor (similar to the stator in a true torque converter but with a considerably lower multiplication factor). Because that helped only minimally with getaway & they were now using only 3 ratios the new 1st gear while not as low as 1st on the older 4 Spd units was still considerably lower than other 3 Spd automatics. More like low on a 3 Spd manual. If I remember it may have been 2.92 or 93 on the bigger model 10 & 3.02 or 03 on the model 5, light duty. That created a wide gap between 1st & 2nd which I believe was 1.56 & 1.58 respectively. And the problem of the seemingly wide gap was exacerbated by the fact that in executing the 1/2 shift the coupling drained & created full mechanical lock-up. Literally, again, like you had a manual trans. With no "slippage" from the coupling, the RPM drop was drastic enough to sometimes lug the engine at low speeds. That's why he said it wasn't really very pleasant driving it in traffic with frequent starts & stops. Anyway, that's probably "clear as mud" but I hope it helps a little. A Powerglide with only 2 ratios & a torque converter that was well matched to the engine & overall gearing as the later ones tended to be, was probably much nicer to live with....

[@scottsullivan1464]

Thank you for such an amazingly detailed response. I know about Corvairs, but very little about the Senior Compacts so all of this is new. I thought GM went off the rails during the 70s trying to deal with the fuel crisis, but in retrospect, they were making big mistakes 15-20 years earlier. @DejaView

[@2packs4sure]

That was fun but my question is what is it that fails,, he mentioned in the previous video that they usually got to about 30000 miles and broke but what is it that breaks? What is it internally that is failing ?

[@0pelman]

They used very high line pressure and they'd leak out of every seal. And they were very sensitive to fluid level. Add an extra half quart to account for the leaks and the fluid would spit out of the dipstick tube. The fluid coupling was internal - behind the oil pump, and it was aluminum and tended to crack Once it wouldn't hold pressure, you lost first gear and reverse. The governor was aluminum and would gall over time, so the signal oil for speed-dependent shifting would wander out of spec and the shifting would get really wild. Sometimes it wouldn't shift at all. Fun fact - the Roto5 did not have the neutral clutch and sprag that the Roto10 used - it relied only on a band wrapped around the rear annulus. If the servo for the band started leaking, you had even more troubles with the first gear start. A friend of mine had a '62 convertible back in the 80s and he called it "rattle and hum". You could always smell the ATF burning as it dripped on the exhaust. As a kid, the family car was a '63 sedan in white. I learned at that early age that I should never repeat the words my dad said when he was working on the slim jim in that car.

[@2packs4sure]

@@0pelman Thank you sir that's exactly what I wanted to know !!

[@oldsjetfire8975]

Did they update the governor to the cast iron one when they rebuilt the transmission? If not I would get the cast iron updated one installed because the original one WILL go bad. With the cast iron one it will greatly improve the reliability but not change the goofy 1/2 shift. They are typically available places. I collected several of them with different part numbers. I think for the three years they had 6 different governors. Different ones for different years and if it was a Jetfire or not.

[@genehart261]

The original hydramatic was an engineering feat similar to putting a man on the moon.

[@rogerdodrill4733]

I think they even used it in tracked tanks

[@georgegray2836]

I drove one of these cars in Driver Education!

[@zappatx]

I've heard a lot about these. Keeps me from buying a 62 Starfire but I sure LOVE my 60 Bonneville with it's wonderfully performing Hydromatic!! I also enjoy the quick take off of the Powerglides. Would like to try the 41 Cadillac version of the Hydromatic though!!

[@NebukedNezzer]

my father bought one of these and took it back to the dealer. they traded him for a demonstrator with a 3 speed standard transmission. it was fine then.

[@lsswappedcessna]

I have the next generation, a '66 F85, with the venerable GM 2 speed and the unfortunately uncommon 330 ci V8, it's a surprisingly good car for its age that I've daily driven in the past and currently shares a daily role with an 04 Suburban. I've driven many modern cars and I can honestly say it rides better than some of them despite having multiple 60 year old components still in place. Has plenty of pep, and thanks to not being the roto-hydramatic it isn't bad in town. Unfortunately the lack of gears means it DRINKS fuel. Measured my combined fuel economy at a staggering 9 miles per gallon!

[@edwardallan197]

I have admired these for over 50 years. Innovation, creative design, beauty.

[@buzzwaldron6195]

Especially the Jetfire: kzbin.info/www/bejne/gKvaZopnp7eApck

[@jeffrobodine8579]

Would be great with a four speed manual transmission.

[@VAspeed3]

My father had the 62 Cutlass with the 185hp engine and 4 on the floor. It was considered pretty quick then.

[@johnkendrick7304]

I would try a manually adjustable shock and you can let it out all the way and give you that nice soft ride

[@kthompso43]

I owned a '61 F85 for 7 years (until '68) and drove it 70k miles. Loved it and no significant issues, except for the aluminum radiator, which needed cleaning several times.

[@patrickflohe7427]

That is so much better than an unsynchronized transmission. One of the many things I hated about a Volkswagen that I had once! it was a 4-speed, but was geared kinda low. I would always have to nearly stop on a 90° turn, if I needed to get into 1st gear again! I have had a lot of cars over the years, including two Chevettes ( they were great! ), and that was the only car I’ve ever had that was actually a piece of crap. -it did handle well, though! I named it “The Hare”.

[@braddietzmusic2429]

Imagine the choice: The Valiant. Or this or one of the other GM stablemates. Beautiful Oldsmobile The Valiant, despite its to-be-legendarily-reliable mechanicals… not so much.

[@TheSourtoast]

My first car was a '61 Super 88 and I lived through this problem in hilly Seattle. I only found out a year ago that it was a bad design, if only we had KZbin in 1994!

[@anman366]

Do you think that the shortcoming with the transmission are a result of it being the "wild west" of engineering back in that time? Or perhaps because GM's divisions had more autonomy back then meaning they had less R&D budget? I do think its cool to see people chime in on the comments about how reliable the 215 V8 was, just not necessarily a great transmission design.

[@gcfifthgear]

My first car was "my father's Oldsmobile"...a '61 F-85 station wagon with the Rockette V-8 and the Roto Hydra-Maric. The engine overheated, and the transmission leaked like a sieve and finally went out on me after a relatively short time. My dad ended up getting me a 1964 Chevelle with a 230 six and a Powerglide! Oddly enough, my dad had a' '63 Star Chief with the four-speed Super Hydra-Matic (which was a tank!)

[@haweater1555]

It wasn't until the GM Turbo Hydramatic 350 of 1968 that the automatic finally and truly came into its own to become installed in easily the majority of cars made.

[@sharkinstx]

I owned a '64 Grand Prix for a couple of years, and I wholeheartedly agree on the operation of the Model 10 "Slim Jim" Roto-Hydramatic. The 1-2 shift with its precipitous RPM drop with the attendant bog and burble , and the RPM rise on the 2-1 downshift, coming to a stop. On mine, the transmission seemed to operate as designed, even with 178,000 miles (I suspect it had been rebuilt at least once). That wasn't the major problem with the car; the rings in the 389 were shot, so it smoked like a chimney. But, the car was only $395, in 1980. If I were to own another one, I'd figure out a way to swap in a four-speed Hydramatic from a Bonneville or Star Chief, or a Turbo 400 (with the switch pitch converter) from a later car.

[@marioncobaretti2280]

Men today are more like spoiled complaining woman. It shifts manly and what you say is bogging is a throaty engine sound to me. Take some testosterone supplements for 3 mos. And then drive it. I love this car. Thnx for sharing with us

[@slowestturbovortec]

We have a 62 Skylark with the 215, but it has the dual path 2 speed. Though also fairly weak, I love that transmission. It is very smooth and almost feels like a CVT.

[@CanizaM]

Dual Path is one of the weirdest GM transmissions. Two planetary gears in the torque converter, and nothing but clutches in the body of the transmission itself. Tiny oil pan held on with a single bolt in the center.

[@russellalbertson1670]

You may appreciate I know a very clever and innovative car buff who figured out how to adapt a GM Turbohydramatic 350 to this aluminum 215 V8 used in the small Olds, Pontiac and Buick in the early 1960s. This is a huge imrovement over the auto trans used from the factory in the early 1960s. This same buff installed the electronic ignition distributor from a Buick 350 V8 into this 215 V8. Additionally he determined the crank from a Buick 300 cu in would bring this 215 V8 up to 262 cu in. The HEI ignition had the coil in center of distributor.

[@novaguy509]

I own a ‘63 Pontiac Grand Prix with the 389 Tri-Power. It had the Slim Jim. The thing was always dripping trans oil. Even after a rebuild. I finally ditched the Roto and installed the 200r4. The best mod I have ever done. 70 MPH at 1950 RPM.

[@craigjorgensen4637]

The Buick Specials of that era 1961-63’s had an even worse transmission. It was a two speed air cooled POS called a Dual Path. They were garbage. All of the the Roto Hydramatics were junk and the Jetaways were just as bad. Ford and Chrysler built much better transmissions in those years.

[@davidkeller2832]

I haven't read every single comment that precedes me but so far, I haven't run across the following facts about this transmission; the Rotohydromatic design allowed the car to be push started analogous to a manual transmission car. I had taken auto mechanic college courses at Oakland Community College back in the early 1980s at their Auburn Hills campus (extremely close to the now-extinct Pontiac Silverdome). There was a Rotohydromatic transmission core available to practice tear-down/reassembly on in that class. The trippy design factor on this transmission is that it had what looked like two torque converters; a conventional variation at the front and a smaller one at the rear. The front torque converter was a bolted-together assembly so you could take it apart to thoroughly clean it out during service/rebuild. The rear converter was much smaller and a sealed unit like later torque converters found on Chrysler Torqueflite 727 and 904, Ford C-4, C-6 and FMX and GM TH-200, TH-350, TH-400 and TH-425 transmissions.

[@b.s.adventures9421]

Look into fox shocks. They are typically for off road applications but are very buttery smooth. With some research you might find something that is cross comparable from a different application.

[@mickvonbornemann3824]

I’ve had a few Leyland P76s with the Australian all alloy 4.4 litre version of that engine, that came with a similar deck height to the Buick 340, they came with the Australian Borg-Warner Single Rail 4 speed, which was quite different to the American equilivent (BWSROD). For example other than a narrow lip around the edge it had a totally flat top plate, unlike the older American BW 4 speed SR.

[@herbienbrian2]

I wonder who had the idea to actually spell out "F Eighty Five". Only in America man and only at GM. God that's dumb. 😂

[@desertbob6835]

Has anyone been able to put a Type 315 Hydra-Matic from a '61-'64 LWB Pontiac or Cad into a full size Olds to replace the junk Type 375 Roto? I've heard that it's doable. I have a very nice '62 Starfire convertible I got dirt cheap due to the Type 375 being trashed. I really don't want to throw money into a Roto, and the 315s were also better performers overall.

[@johnplovanich9564]

A gentleman on Eluethra owns 1 of these.1961 red with white vinyl interior.

[@selenelacaze9883]

There is a running and driving ( but sat a long time ) Olds Fiesta Dynamic 88 394ci , export model, for sale in a shop 5 kilometers from my house here in France, for only 6000€ , and I reaaaaaaally want it. It's all original ( still original air filter box ^^, also has some brackets for some metal oil cans under the hood ) except the exhaust line. So cheap, so rare, sounds so good, looks so good, has a big V8. And I gathered some informations on it, I guess it has a roto hydramatic 375 (Model 10), and it's not that easy to find informations on this transmission, or shops selling parts for them. So thanks for sharing this experience video.

[@kevinvoyer5053]

I remember back in the early 60’s, Dad bought Mom a nice new car after my brother came along. It was a 61 F 86 Sport Wagon, that I remember fondly. There were bucket seats in front and three rows, with enough room for 6 adults, or 5-6 kids and a driver. I’m not sure of the transmission, but I know it had an aluminum V8 w/4 brl dual exhaust, as Dad loved cars. I remember going for ice-cream in sat nights after the softball games, with Dad driving an coaching, plus three wagons full of the team’s players, the other two wagons were a 59 Chevy Impala with a 283, and the other was a 60 Ford Country Squire with a V8 is all I remember. There was this long uphill stretch with two lanes on each side, with a slow speed truck lane on the uphill side making it three lanes. When we all approached the hill we would all start yelling last car to the top PAYS! Well let’s just say Dad never had to pay, but he always did anyway, he was better off that the other two Dads, one of whom was his brother in law, my uncle, in the big Ford. But it was the big Chevy that always came in last, with at least one more kid than the other two! Since then I’ve always loved the sound of the secondaries opening in a 4 brl carb!!

[@jimshields4]

Mark, the roto-hydramatic was not GM’s worst transmission, not even close. As bad as it was, it pales in comparison with the Chevrolet Turboglide. Introduced in late 1957 with the 1958 Chevrolet, the Turboglide was so bad that many cars didn’t make it off the showroom floor. It used cone clutches to save money and couldn’t begin to handle the torque of their V-8 engine. There was a service bulletin one week after introduction and several others in the coming weeks. Chevrolet was forced to offer to replace it with the 2 speed Powerglide for $75.00. GM engineers redesigned the transmission and by 1961 it was considered a good transmission, but by that time nobody would buy it.

[@nlpnt]

Gotta compare with Ford and Mopar's worst transmissions. Slim-Jim and PowerShift were almost exclusively optional on cars that could be had with manual trans (if not on the same trim level), Ultradrive was in way too many auto-only cars. OTOH GM in the '60s and Ford a few years ago abandoned these while Chrysler only dropped the Ultradrive name and made the actual system work reliably eventually, with rebuild kits always to the latest beefed-up spec.