1988-1998 Chevy OBS Truck LS Swap 5.3 Manual Transmission Clutch / Flywheel Install

Part 13: The 1991 Chevy OBS project trucks 5.3 gets a new flywheel and clutch assembly! No 5.3 ever came with a manual transmission from the factory. It’s not a problem though, the 5.3 and 4.8 are basically identical motors externally and the 4.8 and 6.0 both did. Simply order the clutch kit for a 2001 Silverado with those motors, and you can use that kit. Same with flywheel. With ONE exception: the throw out bearing may be different. The clutch kit is based on the engine, the throw out bearing is based on the transmission. So, I will be swapping mine out for the correct one for a '91 manual transmission. Besides, the one provided has a lot of plastic in its construction, I want all metal. That part is going to get high usage, no plastic for me!
Choosing the correct pilot bushing does not have to be a guessing game. Check out the following site for details on how to select the correct size bushing.
americanpowertrain.com/gm-ls-...
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Several key takeaways:
1) When pulling the motor, remove the exhaust manifolds from the heads
2) Cut cross-over pipe from each manifold and disconnect at the “Y”
3) Support rear of transmission and remove trans cross member if pulling engine/trans together
4) If pulling both together, plug end of trans when removing driveshaft or else you will have a big mess!
5) Use and engine tilter, much easier to manage engine if pulling w trans
6) Buy a clutch kit for your application, don’t try to piece it together
7) Use thread locker on all bolts
8) Torq to spec
9) Clean face of flywheel and pressure plate clutch mating surface with alcohol prior to install. It is treated to prevent rust while waiting for installation.
10) Clutch pad will probably only fit in one direction, BUT, “flywheel side” is stamped on one side of clutch disk
11) Use correct pilot bushing!
You can use the link below to find PARTS and TOOLS used on this project that can be found on Amazon. We appreciate your support of the channel. Any items purchased through the provided links provides a small commission to the channel. Thank you and good luck with your project!
www.amazon.com/shop/laurencev...
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New item used in this video with links:
1) 1997-2020 LS1 LS2 LS3 LS6 LS7 LT1 Clutch Pressure Plate Bolts Qty.6 $9.99
www.ebay.com/itm/294194136517
2) Transmission Flywheel Flexplate Bolts Kit LS Engines LS1 LS2 LS3 4.8 5.3 6.0 $17.65
www.ebay.com/itm/284040419783
3) Permatex 27100 High Strength Threadlocker Red, 6 ml $4.99
amzn.to/3oW2BOi
4) RhinoPac® 04-233 - Premium Clutch Kit $144.95 + $12.95 s/h + $12.95 tax = 170.85
5) Power Torque Flywheel Part #NFW1050 Line:PTQ $112.99
total $316.47
Running total of $$ for project Shop Truck:
Part 1 Truck total price $1,308.00
Part 2 and 3 (control arms) $230.76
Part 4 Front brake/spindle rebuild $196.93
Part 5 Cost of Donor + parts sold $265.00
Part 6 Engine parts $438.93
Part 7 oil pan issues $45.04
Part 8 oil diverter $27.01
Part 9 Truck bed removal $00.00
Part 10 Rear suspension lowering/rebuild $226.84
Part 11 LS fuel pump/hose upgrade $99.99
Part 12 Rear disk brake conversion $544.16
Part 13 Pulling engine/trans + clutch/flywheel $316.47
TOTAL PROJECT $4121.54
Disclaimer: This video is intended for entertainment use only, if in doubt as to your mechanical ability, consult a professional to perform the needed work.
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[@codydoyle8963]

Appreciate the video doing the same swap on my 90 Silverado 350 5spd truck

[@qunicetoole7497]

This is what I've been waiting for Mr. Lawrenceville..... I'm trying to do the same thing with my 5.3 Ls swap 95 single cab Stepside with the five speed nv3500 manual thanks for posting the video👍👍

[@laurencevillegarage]

Thank you! I hope it will help you, good luck!

[@Nathan-pm3zy]

Did you have any issues with external slave cylinder?

[@adancarrera8337]

The hard parts done as far as eng harness

[@irwinhernandez5558]

Great video.

[@laurencevillegarage]

Thank you very much, glad you found it useful.

[@qunicetoole7497]

Mr. Lawrenceville the new clutch kit you're using for the '91 OBS is for an 99-03 nbs chevy, the slave cylinder for the NBS is internally mounted, on the transmission spine. .whereas the obs Chevy slave cylinder is externally mounted just below / outside the flywheel housing, so I wanna know....will the external OBS slave cylinder work with this nbs clutch setup?👍

[@laurencevillegarage]

I purchased the kit and it included the pictured throw out bearing. I knew the clutch was right but unsure of that bearing until I had the trans removed and could take a look inside the bellhousing. The bearing I got will work. Inside, the clutch fork looks like most old ones I’ve seen with minor differences. I plan to get a different bearing only because it’s construction is about 2/3 metal and 1/3 plastic. For a high use item, I don’t want one made with plastic. A new one that is all metal is about $25-30. I will also have to replace my external slave cylinder. I didn’t remove it when I pulled the eng/trans and damaged the end of it during the pull.

[@logansmith2694]

Thanks for putting this video up. I'm getting ready to do the same to my 88 1500 4x4 with a HM290 5 speed. I was wondering what all I'd need to be looking into. Any information you could spare would be much appreciated.

[@laurencevillegarage]

I looked at Rockauto for part numbers. You can buy from there or use the site for reference. I looked under 2001 Silverado with 4.8 and manual transmission. They have the Sachs NFW1050 flywheel for about $86, then a clutch kit. They range from about $130-$400. Depending on how you intend to drive your truck, go from there. I think I spend around $200 for a clutch kit. You can get away with the stock slave cylinder or you can upgrade as well. Your flywheel cover plate will not fit like it did before. But, you can trim it up to fit in the areas on both sides of the bell housing to block off the open spaces. Easy enough to do. Want to get really fancy, you can get a Core Shifter for that trans. I did, I'll do a video soon on the install. Good luck!

[@logansmith2694]

@@laurencevillegarage thanks boss, I'll be looking out for the next video.

[@illuminancecrt8930]

Great video, very straightforward and helpful. Once the manual trans is installed, do you have to swap or reprogram the ECU in any way? I am going to swap in a 5 speed into my 93 Chevy truck and the current trans is a 4L60E which is electronic and gets input from the ECU.

[@laurencevillegarage]

Going to a manual transmission simplified things. I am not the programmer, but, there are different adjustments needed for the change. It will simplify the wiring. Only wires to my trans are vss and neutral safety switch. I really enjoy the manual transmission. Good luck!

[@jonnnykash2088]

Where did you plug up the vss and neutral safety switch wires from your factory harness to new 5.3L harness

[@jonnnykash2088]

Swap is done and I’m stuck on that part please help

[@gerardolopez5875]

About time,,, 😄👍👍

[@laurencevillegarage]

I know, I know, I’ve had a lot going on and the truck had to be put on hold. Everything is good now, I should be getting back on track with it. Thanks!

[@AntonioMartinez-pr3wb]

I'm in the middle of attempting this and not going so smoothly, It may be from attempting to piece together u had purchased before watching, it appears to be the correct bearing and clutch plate and I think pressure plate, but it seems like I got to squeeze together in order for the mating surfaces to touch so in other words the cluch disc is not letting the pressure plate unless I squeeze them together with the bolts not by much maybe an eighth is this normal

[@laurencevillegarage]

If you are using the 1050 flywheel, it should only fit one way (although I have never tried to turn it around to see if it could fit), and a clutch kit, it should all fit well. If you have pieced all the various parts together, that could be an issue. Be sure you are not using the LS throw out bearing, it won't work. Use the correct T O bearing for the trans you have. It should all fit together with some "squeeze", but still have room for the clutch forks to move enough when depressing the clutch for it to disengage. If it fit loosely, that's not right either.

[@evanbennett4308]

Great video everything about it. But I have one question are you using external slave cylinder or internal with the lines coming off the throwout bearing

[@laurencevillegarage]

Good question! I am using the stock '91 slave cylinder. Actually, it is new because I damaged the old one while removing the engine/trans together. A good point to note that I have not seen in ANY other video is, when keeping the older trans with the LS motor, the flywheel, clutch and pressure plate are for a '01 4.8 Silverado. The throw out bearing that comes with that kit does not fit the older trans. In fact, it looks very different. So, I used the correct throw out bearing for a '91. HOWEVER, here is the catch. When doing this, you need to measure the distance the bearing has to move against the new pressure plate fingers. The "rod" that fits the slave cylinder to the clutch release fork may need to be replaced with an adjustable one. Mine seems to need this because the rod is too long. I didn't realize this until the hydraulic clutch system was bled. Afterwards, the truck would not start. Turns out, because the rod was too long, the clutch pedal would not go in quite as far as before. Therefore, it did not press the neutral safety switch preventing the truck from starting. I am working on this as we speak. A pretty simple fix, but, I should have realized that with the 2 throw out bearings looking so different, things would change. At first (before the clutch was bled) the pedal went in far enough for the motor to start (first time I might add!). After bleeding, it seemed like it still went in far enough, but no, about 3/4-1" short of pressing the ns switch. Now you know!

[@evanbennett4308]

I used a brute 1377c throwout bearing and stock external slave and made a custom push rod

[@chargerrt181]

Did the 1377c throw out bearing work for you? And how long did you cut the push rod? When I went to turn on my truck my clutch pedal only went about half way down using the original slave and throw out bearing

[@joshbeasley9423]

​@@laurencevillegarageit won't let me see all of this reply what bearing did you use

[@laurencevillegarage]

@@joshbeasley9423I used the bearing that was correct for the type of transmission.

[@80gritt]

Did you use the stock clutch fork with the stock throwout bearing from for the obs or did you change to a different throughout bearing?

[@laurencevillegarage]

Yes, stock clutch fork and throw out bearing for the obs.

[@crestflock]

I have Chevy 94 single cab and I have 5.3 Ls ready to swap this clutch works for my existing manual transmission? Thank you for sharing it.

[@laurencevillegarage]

Yes, the clutch will work. The clutch you want is actually for the engine. The throw out bearing is for the transmission. In my case it worked out fine with no issues. I've had it swapped now for awhile and have had no issues with it...

[@MiguelLopez-qd5ti]

Buen dia yo estoy haciendo el mismo proyecto y no encuentro el aro volante dentado por ninguna refaccionaria o yonke me podria facilitar de informacion donde consiguio usted el aro para terminar mi troca

[@laurencevillegarage]

Try SACHS NFW1050 or LUK LFW387 at Rockauto.

[@derrickfarrow5395]

I couldn't find the links for the clutch kit and pilot bearings.

[@laurencevillegarage]

I checked, and the links provided in the description below the video are working. All the information is there.

[@eddiemedia7379]

What motor mounts did you use? I bought dirty dingo and I’m 2/3 inches to forward to be able to bolt up the transmission

[@laurencevillegarage]

For my swaps I use metaltek manufacturing. Excellent quality and no issues. I pulled my motor forward so the low mount a/c would clear a bit better (still had to notch the frame). My trans bolted up w no issues.

[@laurencevillegarage]

Also, try switching the upper mounts from left to right, they should not be 2 to 3 inches off.

[@jameswiz]

I have a 98 k2500 w/ 454 and power brakes that run off the power steering. I want to LS swap the truck. I'm not sure about the flywheel spacing and mounting up AC as well as the power brakes/ steering.

[@laurencevillegarage]

You did say flywheel so I assume you have a manual trans, if its an automatic, then it would be a flex-plate or flywhee. and that is quite different. While I have not swapped a 4wd, you can use your existing trans but use a "dished" flexplate (assuming auto trans) from a 4.8, 5.3 or 6.0 (there are a few variances here so it depends on what year motor and size), and adapter (`$30). A/C depends on a number of things such as what style of compressor and mounting location, p/b and steering should be able to be used. That is the quick answer. You would really need to sit down and go over more details and specifics to make sure how this applies to your specific swap plan. Can't be done in this amount of space. But, these would be the highlights.

[@jameswiz]

@@laurencevillegarage I said Flywheel as it's a manual. I know the bell housing depths are different on an LS than older SBCs, so I'm wondering if I would need a special spacer for the flywheel so the input shaft fits the pilot bearing. Or did the flywheel and clutch kit you purchased have the offset built in?

[@laurencevillegarage]

@@jameswiz Ok, with the flywheel, what I did was order a flywheel and clutch kit for an '01 4.8 Silverado. The flywheel with have the correct "dish" to it and the clutch/pressure plate will be correct. In the kit it included 2 different size pilot bearings so you will need to measure the distance the transmission input shaft extends past the bell housing mating surface to determine which of the 2 you will use. Info is included in the clutch kit. I then used a stock replacement throw out bearing for the type of trans I had. All is well up to this point. Now, what is going to be different is the small shaft that goes between the slave cylinder and the clutch fork. Because the flywheel is spaced back ~.4 inches and the small differences in the various brands of clutch products, that shaft will need to be shortened. I cannot say how much on your application. There are adjustable ones out there, or you can shorten your own until you get the correct length you need. Before I made this adjustment, and before I would start the truck, I raised the rear tires off the ground and inch or 2, just in case something wasn't right, I could avert a big problem. Before bleeding the clutch all went in fine. After bleeding is when I knew something was amiss. Truck would not start. Turned out that when depressing the clutch pedal it stopped short of the n/s switch. When I pressed the switch with my left hand and turned the key with my right, it started. While in neutral, I noticed the right rear tire turned a bit. I could put my hand on it and it stopped easily. That is when I realized I did not take into account the difference in the distance the throw out bearing was to the new clutch. The flywheel is now closer to the bearing than before and making an ever so slight contact trying to engage the clutch.

[@jameswiz]

@@laurencevillegarage how did you know the 4.8 clutch would fit your input shaft? My 98 has a 454 in it with the NV4500. It EATS clutches, so last time I put a ceramic clutch in it. I'm hoping to reuse the same clutch if I can. I'm not sure what size is stock on an LS, or the gen6 454... I guess I'll have to dig into that a little

[@laurencevillegarage]

@@jameswiz From research I have done in the past on various transmissions adapted to the LS motors. The later model NV4500 and the '91 5lm60 that I have both are 10 spline shafts. Having said that, I've never replaced a 454 with an LS. You many need more parts than I did to make your conversion. Do your research and see who has been where you want to go to get the best information. I don't want to lead you on a path based on what I have "heard" or "read". I try to give out information on what I have actually done so I know it will or won't work. The caveat to that is everyone's combination can be a little bit different so look everywhere for info and try to find more than one source to back up your findings. Good luck!

[@Nathan-pm3zy]

How did you bolt the NV3500, I’m having an issue with the external slave hitting the oil pan. Do you have pics or a video

[@laurencevillegarage]

My trans was the HM290. Not sure of the difference (if any) in the bellhousing of the 2 trans types. What pan are you using? I used a 98-02 F-body LS1 style pan with no clearance issues.

[@Nathan-pm3zy]

Not sure it came with the 4.8, I bought a 302-1 and still have the same issue

[@Nathan-pm3zy]

Wish I could send a pic

[@Nathan-pm3zy]

@@laurencevillegarage which external slave cylinder may I ask

[@laurencevillegarage]

Without seeing the area of interference I can't say. Another option may be to go with a hydraulic throw out bearing. Not sure how that would fit withing your bell-housing. Again, without seeing it I can't say.

[@removeableskull7446]

Could I use a bushing or does it have to be a bearing for a readon

[@laurencevillegarage]

I assume you are referring to the pilot bearing? Needs to be a bearing, a bearing doesn't wear like a bushing would. That transmission input shaft would wear a bushing out much quicker than a bearing.

[@removeableskull7446]

Ok I’ll check it out

[@felipealvarado8410]

I got 95 Could you use a v6 manual tranny to do a 5.3 swap or I’m going need a whole new tranny too?

[@laurencevillegarage]

That is what I did with my '91. It is running the original 5LM60 manual trans with the 5.3. My 5.3 is totally stock, no mods. I'm not sure of the limits of the 5LM60, but, I am not racing or power shifting the trans. I drive it normally and do get on it at times, but not between shifts. Time will tell, but so far no issues at all. Soon I will be adding a Core shifter to it to make the shifts more precise and shorter. Stay tuned.

[@ivanignacioortiz3284]

It should be same for nv53500??

[@laurencevillegarage]

The clutch assembly I would say yes. Items that may be different would be pilot and throw out bearing because they would be specific to the transmission.

[@cesaresparza7047]

What throw out bearing did you use or you used a spacer

[@laurencevillegarage]

I bought a new bearing for the ‘91 transmission. The throw out bearing in the clutch kit was for an ‘01 which is different and looked like it was half metal and half plastic. The new correct bearing for the ‘91 is all metal, about $28.

[@davidgamer968]

@@laurencevillegarage can you give us a link for the bearing and clutch

[@laurencevillegarage]

@@davidgamer968 yes, I have a link in the description below the video, along with the price I paid for it. If the link does not work, let me know. Thanks

[@ndog808]

I do not see a link for the all metal throw out bearing for the '91.. got a part number?

[@Notjay95]

What transmission did you use for your swap? The original 5lm60?

[@laurencevillegarage]

The original transmission, it is the HM290.

[@Notjay95]

@@laurencevillegarage did you have to alter your driveshaft or buy a different size?

[@laurencevillegarage]

@@Notjay95 No, stock driveshaft. Everything lines up perfectly.

[@tre9563]

I have a question I have the 4.3 5 spd and the 10 bolt rear 1st and 2nd gear is really short can I put in a different gears in rear for example like 3.75 or 4.10 to get a longer 1st and 2nd range with low rpm???

[@laurencevillegarage]

Going to a 3.73 or 4.10 would make 1st gear almost unusable. Too steep for a V6 imo. You would probably start in 2nd and shifts would be quicker than before. Check to see what you currently have. You didn't mention what year your truck is, but both my '91 and '95 V6 trucks had a 3.42 rear gear. If you are wanting a longer gear than a high 2 series would be needed.

[@ndog808]

Are the parts the same if I'm mating a 5.7 ls1 to 5lm60?

[@laurencevillegarage]

The parts are not the same, but the process would be. Do some checking around first.

[@ndog808]

@@laurencevillegarage man I'm getting different info. Do you know what could be different? 5.3 vs. 5.7 LS?

[@laurencevillegarage]

@@ndog808 I don’t want to lead you in the wrong direction. I have not put a 5.7 LS1 together with this transmission. Having said that, if I look at Rockauto, they do not show the same flywheel for a 5.7 and 5.3. There may not be any difference between the two. If it were me, I would get the correct flywheel and clutch for the 5.7. Then measure the distance on my current transmission bell housing to determine the correct input bearing to use and go with a throw out bearing made for the transmission. The last variable will be the shaft length from the slave cylinder to the clutch fork (assuming a hydraulic clutch). In mine, a stock one for the original transmission works. But, when you are mating up parts that were never a combination used by GM, you may have to play with it a bit. It can be done.

[@ndog808]

@@laurencevillegarage excellent information, much appreciated!

[@laynepewitt7118]

Just curious is that tranny the 5lm60?

[@laurencevillegarage]

Yes, it is.