TH350c Rebuild?
+ Reply to Thread
Page 1 of 4 1 2 3 4 LastLast
Results 1 to 14 of 56

Thread:
TH350c Rebuild?

  1. #1
    Super Moderator HammerDown's Avatar
    Join Date
    Dec 2007
    Location
    The Right Coast/SE-PA
    Posts
    5,488

    Question TH350c Rebuild?

    I'm referring to, the TH350c 3-speed with electronic converter lock-up (81 Vette)

    Because I have 'trust issues' with local shops I'm considering rebuilding my TH350c transmission...how scary is it in this transmission?

    BTW, the trans is operating just fine however it's leaking from what research tells me is the pump seal.

    So, I figure being it's 31 years old and has 127,000 miles on it I would go thorough it.

    Thanks for any suggestions, Ray
    <img src=http://www.performanceboats.com/gallery/data/500/medium/06-30-11_1234.jpg border=0 alt= />

  2. Remove Advertisements
    PerformanceBoats.com
    Advertisements
     

  3. #2
    Member tmoore's Avatar
    Join Date
    Nov 2009
    Location
    North Texas
    Posts
    61

    Default

    Th350 is one of the easiest transmissions out there to build. The lockup doesn't add much to it.
    Get an ATSG manual and you shouldn't have any problem.
    Buy a lip seal tool.

  4. #3
    Senior Member shan's Avatar
    Join Date
    Jan 2008
    Location
    Yuma
    Posts
    1,834

    Default

    Quote Originally Posted by tmoore View Post
    Th350 is one of the easiest transmissions out there to build. The lockup doesn't add much to it.
    Get an ATSG manual and you shouldn't have any problem.
    Buy a lip seal tool.
    And a clutch compressor to get the low/reverse piston apart in the case, and a pair of slide hammers to get the pump out..
    Quote Originally Posted by Spike Morelli View Post
    Golfers and Fishermen are third rate bullshitters, compared to lots of hot boaters....

  5. Remove Advertisements
    PerformanceBoats.com
    Advertisements
     

  6. #4
    Super Moderator HammerDown's Avatar
    Join Date
    Dec 2007
    Location
    The Right Coast/SE-PA
    Posts
    5,488

    Default

    Thanks for the feedback,

    I ordered what 'should be' a comprehensive instructional step-by-step DVD on tear down, inspection and rebuild on the TH350 & TH350c transmission.

    To fully tear my TH350c apart I wasn't sure on what 'specialty' tools were required.
    ^ I did see on YouTube, someone got the pump out with a large screwdriver behind the throttle-body, but didn't show details...any one know how???

    Researching so many different 'rebuild kits'...prices varying from $80 all the way up to $495 and that's without a reman torque-converter!

    Hopefully no hard parts are needed or, my local transmission shop will sell me "good used" or new parts.

    Thanks again, Ray
    <img src=http://www.performanceboats.com/gallery/data/500/medium/06-30-11_1234.jpg border=0 alt= />

  7. #5
    Member tmoore's Avatar
    Join Date
    Nov 2009
    Location
    North Texas
    Posts
    61

    Default

    I've improvised on most all the tools before... a couple bolts a short chain and a hammer will get the pump out.
    Usually any of the kits with all the frictions seals and bushings should get you fixed up for around $150.

    If I were you I would still get an ATSG manual. It's money well spent.

  8. #6
    Super Moderator HammerDown's Avatar
    Join Date
    Dec 2007
    Location
    The Right Coast/SE-PA
    Posts
    5,488

    Default

    Quote Originally Posted by tmoore View Post
    I've improvised on most all the tools before... a couple bolts a short chain and a hammer will get the pump out.
    Usually any of the kits with all the frictions seals and bushings should get you fixed up for around $150.

    If I were you I would still get an ATSG manual. It's money well spent.
    Thanks for the feedback...

    The DVD is good, really good and even shows how to get the front pump out, with a large screwdriver.

    However, the DVD isn't about my TH350c but the TH350.

    Not sure how much I'm missing out on or what needs to be tested/checked on the 3-speed electronic lock-up TH350c ???

    I may still get the ATSG manual too.

    To remove the in-case Low/Reverse Piston it appears I will need the GM REAR CLUTCH SPRING COMPRESSOR -Trans Tool T-0151 $27.00 on eBay
    <img src=http://www.performanceboats.com/gallery/data/500/medium/06-30-11_1234.jpg border=0 alt= />

  9. #7
    Senior Member
    Join Date
    Dec 2007
    Location
    Olympia, Washington
    Posts
    588

    Default

    Valve body is different, some changes in the front pump and obviously the torque converter. Highly recommend a mild shift kit. If high horsepower engine their are a few other upgrades you could do also. Almost all the gear train is the same between the two. Make sure you replace the thru case connector o ring, and if it was me I would replace the lock up solonoid with a quality replacement.
    Last edited by Oldelmn8tr; 01-31-2014 at 11:51 AM.

  10. #8
    Super Moderator HammerDown's Avatar
    Join Date
    Dec 2007
    Location
    The Right Coast/SE-PA
    Posts
    5,488

    Default

    Quote Originally Posted by Oldelmn8tr View Post
    Valve body is different, some changes in the front pump and obviously the torque converter. Highly recommend a mild shift kit. If high horsepower engine their are a few other upgrades you could do also. Almost all the gear train is the same between the two. Make sure you replace the thru case connector o ring, and if it was me I would replace the lock up solonoid with a quality replacement.
    Thanks for the feedback,
    The 81 is only rated at 190 hp (pathetic I know) but to make the engine a little happier I just removed the catalytic converter, smog pump, heat risers...and will be removing the egr. Basically all emissions/smog crap will be gone.

    With only 190 hp, what would a mild shift kit do for the car?
    I'm definitely not interested in any neck snapping or banging shifts...what kit would you recommend?
    BTW...my dana-44 is a very weak aluminum differential, that I just rebuilt, so hard shifts are a no-no.

    Thanks
    <img src=http://www.performanceboats.com/gallery/data/500/medium/06-30-11_1234.jpg border=0 alt= />

  11. #9
    Senior Member rogerroost's Avatar
    Join Date
    Oct 2009
    Location
    Maple Ridge B.C. Canada
    Posts
    536

    Default

    if it was me ,for a vette . i would find a 350 ,not a 350c. use a transgo stage 2 .lose the 1-2 accumulator spring,heavy duty intermedate sprag race , get the direct clutch piston cut down so you can put in an extra clutch plate(5) and steel . and a bit more stal in the convertor (not to much) .It'll work great

  12. #10
    Senior Member
    Join Date
    Dec 2007
    Location
    Olympia, Washington
    Posts
    588

    Default

    A mild shift kit will make the trans life longer and will firm up the shifts but will not be neck snapping. In my opinion Rogerroost's recommendation is going a little far for what you want to achieve. Transgo does make a nice kit.

  13. #11
    Super Moderator HammerDown's Avatar
    Join Date
    Dec 2007
    Location
    The Right Coast/SE-PA
    Posts
    5,488

    Default

    Thanks for the feedback fellas,
    A different transmission will not be happening, maybe if I was still in the earlier years of owning this car but realistically, at my age and owning it since 1981 I just want to go through the TH350c, stop the leak, freshen it up and put it back in the car.
    I could see a mild shift kit, but first order of business is to find out what normal wear items need to be replaced and what hard parts may need replacing > hopefully I won't see anything ugly.
    <img src=http://www.performanceboats.com/gallery/data/500/medium/06-30-11_1234.jpg border=0 alt= />

  14. #12
    BTC cardcarrying member sunkisst's Avatar
    Join Date
    Jan 2008
    Location
    Chantilly Va.
    Posts
    1,075

    Default

    Ray, I cant manage to locate my reverse piston tool. I did find my drum press which you will need one of. Lemme know if you need it. I don't do transmissions anymore.

  15. #13
    Member
    Join Date
    Oct 2013
    Location
    Havasu Az
    Posts
    55

    Default

    Your leak is most likely due to hard rubber. That being the case make sure you get the low-rev piston tool so you can replace those seals. Get a book and tear into it. That's the trans I cut my teeth on many many moons ago. 5-6 of them a day on the bench. About 30 yrs ago. With it being a lock up make sure you replace the converter because there is a clutch inside of it and I'm sure with that age the material has flaked off. Otherwise you'll get a shudder when it locks up. Good luck have fun it's just a bunch of parts.


    Sent from my iPhone using Tapatalk

  16. #14
    Super Moderator HammerDown's Avatar
    Join Date
    Dec 2007
    Location
    The Right Coast/SE-PA
    Posts
    5,488

    Default

    Literally, just today...it's out.
    And is this the tool being needed?
    GM Rear Clutch Spring Compressor Trans Tool T 0151 to Remove Low Reverse Piston | eBay
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

Name:	Trans Out.jpg 
Views:	95 
Size:	113.9 KB 
ID:	481202  
    <img src=http://www.performanceboats.com/gallery/data/500/medium/06-30-11_1234.jpg border=0 alt= />

+ Reply to Thread
Page 1 of 4 1 2 3 4 LastLast

Quick Reply Quick Reply

Register Now

Please enter the name by which you would like to log-in and be known on this site.

Please enter a password for your user account. Note that passwords are case-sensitive.

Please enter a valid email address for yourself.

Please select your insurance company (Optional)

Log-in

Tags for this Thread

Digg This Thread

Posting Permissions

  • You may post new threads
  • You may post replies
  • You may not post attachments
  • You may not edit your posts
  •  
 

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95