Replacing a TH350 Shift Shaft Seal

Buy Tool: amzn.to/2EAeLDH
Buy Seal: amzn.to/2EvCncp
This video shows the procedure to remove and install a new seal in a TH-350, TH-400, 700R4 or 4L60 transmission. There is a removal tool available online or at NAPA for about $6. The tool part number is Evercraft 7769250. If you think your transmission pan seal is leaking, you might want to check your shift linkage seal first because if it is leaking it will run right along your pan seal which can be very misleading!

[@AaronWerner]

Why would anyone give this a thumbs down...best video so far on how to do this...Thanks for sharing. took the time to give you the part number.

[@CoolStuffGuysLike]

Thank you! I appreciate the good feedback.

[@mookandairin]

Awesome video. I am about to change the shaft also on my th400. Knowing the tool is a "must have" and Napa of all places has it cheaper than anyone else is a plus. usually Napa is more expensive than the rest of the parts houses so their price surprises me to be honest. Thank you again for sharing the knowledge you hold and making a easy to follow video. well description to what you were doing. Well done

[@TyroneShoolaces-f8e]

AGREED, in pa sask napa just quoted me 191 for one brake caliper and cdn tire had same caliper for 110, 80 bucks LESS or about 45% more money !

[@LA92]

Thank you very much for filming this process! Fine explanation and nice work! Now its clear and no questions

[@thangtran8281]

I was able to replace this seal on my F150 following your video. Thank you.

[@jackieliner3812]

Wow, this video is great, I just watched one on here we’re the guy actually removed the pan and disassembled and removed shaft,, this is soo much easier, thanks for sharing

[@ericlambousy6717]

Simple. I am no longer questioning the procedure in my mind. thanks, Cool Stuff!

[@erics.9175]

Performed repair today with recommended too. Success. No leaks!

[@erics.9175]

Leaked after seal replaced. Got another seal. There are differences. This one looked like it would seal better as it was deeper (thicker) and the rubber was bigger. We’ll see.

[@bluegrasskid]

@@erics.9175 how’d it go? Did you drain the transmission pan first?

[@timstangohr7859]

The remover tool is threaded, so you can turn it into the seal to grab it for removal. When installing the seal, I used a pick tool to get it over the flats of the shaft

[@betosanchez8318]

DOES THE TRANSMISSION NEED TO BE DRAINED IN ORDER TO REPLACE IT?

[@funfun8095]

No

[@daviddoolittle7367]

Do you lose a lot of fluid or just a little?

[@robertyork498]

Great video, thank you ! heading to NAPA, just a little drip looks like hell in my driveway

[@moecardoc]

Great video. Can this be replaced with out the special tool?

[@mcgyverinstituteofninjatech]

Do you have to drain the transmission fluid before you replace the seal?

[@torrancecody845]

Great video I have a 1976 corvette with no reverse gear in my th350 transmission but forward works just fine how do I fix this ?

[@cj7girl280]

How do you take the selector shaft out? The threads are all chewed up... Need to replace it.. Does it just unscrew once the seal is out? Thanks for the video...

[@michaelbertovich]

Did you drain the fluid first ?

[@ericlambousy2417]

Thank you sir for posting this video. Now I understand how to use the tool and i know i have the ability to do it. Looking for a dry transmission pan afterward. Appreciate the help!

[@ramonvalderrama2192]

Good morning, one question, what is the name of that part that is changing because my C10 pick-up Chevrolet has a can of oil where the odometer wire is, and I think it's right there

[@ramonvalderrama2192]

Buenos días, una pregunta como se llama esa pieza que esta cambiando porque mi pick-up C10 Chevrolet tiene un bote de aceite por donde esta la guaya del cuenta kilómetros, y creo que es por ahí mismo

[@78monte94]

Thank you for the video of exactly what I needed

[@swsisco5]

Do I need to drain my transmission pan before replacing this seal? i just installed a new gasket on the pan and saw that i have a small leak on the shift shaft.

[@bluegrasskid]

Should the pan be empty or full before doing this?

[@silvosshop]

Anyone have an answer to this question?

[@jasonfernie1494]

@@silvosshop Full is fine

[@FullChokeFowl]

Excellent video, brothaman. Helped me out a lot.

[@danielpotter3017]

Dumb question, do you have to drain the trans fluid before doing this?

[@joshuamoore24_7]

Did you get the shift shaft seal puller tool at NAPA also?

[@combatadvisor]

How did you get the shift selector off?

[@jasonfernie1494]

Remove the nut thats on the end of the shaft.

[@gregl2249]

Does this work for 79 gmc truck ?

[@tedheierman1181]

I'd really like to see this done with the trans still in the car!

[@CoolStuffGuysLike]

The trans is still in the truck. The body is off (obviously). With dual exhaust you could run into a tight situation depending on how it is routed but it would depend on the car. There are so many cars and trucks that had a TH350.

[@foxjerry1]

Glad to see someone who doesn't have to wear wussy mittens. Good vid.

[@chrismorgan8641]

Hi all - great vid - thanks. Anybody out there know if this approach can be used on a Ford cruise-o-matic transmission (out of a '63 Thunderbird)?

[@OperationBlueberryExpress]

About how much fluid do you suppose you’d lose if doing this while the transmission is still in the vehicle? I’m about to replace the seal on mine. Replaced the pan gasket twice, output shaft seal, and I’ve still got transmission fluid dripping onto my exhaust. The only other place I can think is this seal. It’s the only place I see that’s wet on the transmission

[@CoolStuffGuysLike]

Almost none. Maybe a few drops. If it isn't coming from there, check the seal where the dipstick goes in. It may run around and trick you as to where it originated. The only other big leak source would be the input shaft, so hopefully it's not that.

[@OperationBlueberryExpress]

@@CoolStuffGuysLike torque converter is bone dry. I can’t see or feel any fluid around the dipstick tube but I’ll definitely be sure to do a more through inspection. Thanks for the response!

[@FullChokeFowl]

@Trash Boat I'm going thru the same thing on my squarebody...the dipstick is the only thing not leaking lol. The modulator seal was leaking, the selector shaft (like this video) and the accumulator seal was leaking. I replaced my pan gasket twice before I found all those other things.

[@lauradahlus]

Also, I know you have the 350 but would you know why my shifter shaft moves slightly in and out of the housing?

[@janneuyen1019]

mooie uitleg ben goed geholpen dankjewel

[@corywilliamsmith]

Ive read on some forums that an old shaft seal causes the neutral safetyswitch/ range sensor to malfunction & (because it builds up a lot of transmission fluid and then obviously dirt and grime) cause a hesitation from 1-3. When you take your NSS off is there a certain protocol to follow? I think it'd be important to note if so. I.e. Do you need to leave it in park, or neutral when removing said NSS? Thanks for the content !

[@CoolStuffGuysLike]

That is a good question and I don't know the answer to it. If you find out a procedure for the neutral safety switch let me know. Honestly I don't know if that truck has a NSS off the top of my head.

[@josephrojas240]

What's the part number on the seal?

[@bretwinterfeld6175]

Great video! Really helped me out!

[@widtrak77]

I bought this but it doesn't seem to fit over my shift shaft! Mine is a TH400 but I think it is supposed to work on it. I noticed yours was a little tight do you just need to hammer it on I'm afraid to break it

[@CoolStuffGuysLike]

You should be able to tap it in with the installer tool, or a deep well socket. If it really looks like it doesn't fit then maybe double check the seal. You could put a little oil on it to make sure it slips on good also.

[@widtrak77]

@@CoolStuffGuysLike its not the seal I'm referring to its the actual tool itself. The Napa tool will NOT slide over the shaft. Its just too small a diameter. I ended up ordering one on ebay from a different manufacturer. I'm going to try it tomorrow I will let you know.

[@schutzhund3933]

widtrak77 did you replace the seal? I have the same problem, tool won’t fit over shaft. Can’t find any info about it.

[@widtrak77]

@@schutzhund3933 I did replace it and I'm trying to remember I believe I ordered another tool and it was still very tight but better I was able to tap it on I think with a little lubrication but I had to attach vise grips and tap it with a hammer to get the thing off. It was a pain in the tail good luck I hope you get it to go on

[@schutzhund3933]

widtrak77 thx. Trans shop said tool was factory size, so maybe have to beat it on! Thx for reply!

[@tsimshianman]

I bought the exact tool and followed your directions but the tool wouldn't grab onto the seal. I must have tried 20 or more times to no avail. Now I have to dig it out with picks. It isn't coming easily either. The tool appears to have worn out after all those tries.

[@tsimshianman]

John Smith thanks, I took it to a shop that would do it. Oddly most didn't want to do it or referred me to a tranny shop that wanted $200. The mechanic using the exact same tool got it out first try and still billed me $150! He had the benefit of using a hoist whereas I was trying to do it laying on my side. I have a neck injury to add to the mix. The car is a 24 T-Bucket with side pipes which made it challenging to get close enough to it. He said you have to apply pressure and turn. At that point I was just happy to get back out crusin!

[@journeyquest1]

If the shaft has a groove worn in it may still leak,

[@aubreychaparral32]

So to replace the shaft itself would you do the same thing?

[@jasonfernie1494]

@@funfun8095 Bend the nail and it will then come out. If your careful you can then put it back in and straighten as you go.

[@markdahl3509]

Good job thanks I’ll try it tomorrow !!

[@Mancavechannel]

Thanks for the info

[@darrylyoes414]

Thank you so much!

[@viewerslikeyou6326]

Do you think this is doable when the trans is still mounted in the car?

[@CoolStuffGuysLike]

Definitely. It will be a little tight getting a hammer around the exhaust but you shouldn't have too much trouble. I would figure most people do it with the trans still on the car. In my case it is a Chevy C10 with the trans still mounted but I had the cab removed to do some frame work so it was a lot more open

[@viewerslikeyou6326]

Thanks man, this video was a lot of help.

[@donrutter6765]

Depends, cars like corvettes have low floor pans that you cant get tools in there to do it.

[@chamberlin1]

For BMW E53 X5 with the GM transmission you might have to remove the driveshaft for best access, but otherwise yes in the car is fine!

[@LegendaryWoke]

I'm watching for a C-10 Also! Thanks for the vid!

[@freemindas]

So the whole transmission must be dropped just to replace that little seal ?

[@CoolStuffGuysLike]

No, you can get to it from below just fine. This was on a pickup that had the body off anyways which made it a lot easier to show.

[@freemindas]

@@CoolStuffGuysLike the thing is I have a Mercedes w203.

[@strengthfortoday]

This is truly amazing but no place to buy tool in Canada legit. 🤦‍♂️

[@duvalcampbell5796]

Change my seal but it’s still leaking

[@richiesisneros4975]

The shaft is still in the trans?

[@chrisohandley6471]

Yes

[@richiesisneros4975]

Are the seals standard size? Or common?

[@CoolStuffGuysLike]

Hi Rich. The seals should be standard across GM TH-350, TH-400, 700R4 or 4L60 transmissions. I put a link to buy the seals from amazon in the video description.

[@johnmarcus317]

Why were you changing it???

[@CoolStuffGuysLike]

It was leaking from the shift shaft seal.

[@albertano6969]

How bad was your leak ???

[@straighttimestirrups]

And here I thought you were changing it just to make a video for KZbin Fame, lol.

[@rodneyrivas6911]

Was your trans pan leaking on one side? That’s what mine was doing

[@Guitardude-hm2fl]

Could you do this with a pick rather than the special tool?

[@CoolStuffGuysLike]

You probably could. You would want to be careful not to scratch the shaft or the bore.

[@7easternrider]

The seal that I'm finding are pure rubber with no metal housing. Will that make a difference. Do you think that's fine.

[@CoolStuffGuysLike]

It is hard to say. I could imagine a more modern seal design could be better than the original that had the metal. I would fear that it might work it's way out. They are pretty easy to change though, so worst case you may just end up doing it again. I got my seal from NAPA. You should be able to get a normal one from there if you can't find it elsewhere.

[@TechsHelpingHand]

Thanks!

[@mr.goodpliers6988]

Awesome

[@swissarmychainsawadams9541]

The odds of you needed a new selector shaft are pretty good Here is a two part video on replacing that: kzbin.info/www/bejne/bmKuinefhqeZjac

[@TyroneShoolaces-f8e]

nice demo but your tranny is bone dry, mine is all wet lookin and probly needs a output shaft seal as well

[@jasonfarnsworth5880]

Hey, PS hit it again lol