Im Jacob and I have transmission problems..

[78Scottsdale]

Hello im new and my 78 C10 has been having transmission problems, this is my first chevy but defiantly not my first go around with classic vehicles. So as far as my problems go, the first TH350 took a dump so i swapped it with a low cost ($300) used replacement off craigslist. B&M pan, came with converter, the small amount of fluid in the trans was clean and didnt smell burnt. Since installation my first and second gears put down power, no chatter, the shift from first and second is firm and smooth (possibly a stage 2 shift kit?) and the shift from second to third seems like it takes some time i almost need to push it into gear (give it more throttle). third grabs initially getting on the interstate but as i continue to accelerate my rpms go through the roof and it almost feels like im driving on ice. In the first 4 days for installing the trans 3rd has hooked no problem on the interstate twice and has spun twice. So i take back roads now to save fuel and reduce engine stress. Lastly some mornings it has stalled when accelerating from a dead stop within the first 1-2 miles of driving (lettin truck warm for about 5-10 min). Converter? Check ball? sorry for it being long winded just need to put all my information out there.

*if theres a better place for this to be posted please let me know

 

[Dan Miller]

Welcome from Indiana !! I'm not a transmission guy , but this site is full of knowledge, tips and opinions so I'm sure someone will add some useful info that will hopefully help

 

[Old77]

 

[Preston]

Welcome to GMSB from Virginia

 

[dvdswan]

Welcome to the site.

 

[Doppleganger]

Sounded like the intro to a support group. lol

You must be registered for see images attach

 

[Snoots]

Vacuum modulator maybe?

 

[HotRodPC]

Do you know how long it sat before you bought it? Maybe some dried seals and as it warms up and the fluid gets thinner the fluid is able to get around the drum seals and the clutch piston grip fades away. It might be worth a try to use Auto Trans Conditioner. They do help many times in a situation where it has sat for a long period of time. If the trans conditioner can soften the seals and that's the problem it should only get better and better with more driving and warming the seals.

The other thing that can happen, is the seals stick to the drum instead of slide with the piston. If they're stuck badly, and that piston does move then it's possible to damage the seals and there is no correcting that without a rebuild.

 

[animal]

 

[jjester6000]

Hello im new and my 78 C10 has been having transmission problems, this is my first chevy but defiantly not my first go around with classic vehicles. So as far as my problems go, the first TH350 took a dump so i swapped it with a low cost ($300) used replacement off craigslist. B&M pan, came with converter, the small amount of fluid in the trans was clean and didnt smell burnt. Since installation my first and second gears put down power, no chatter, the shift from first and second is firm and smooth (possibly a stage 2 shift kit?) and the shift from second to third seems like it takes some time i almost need to push it into gear (give it more throttle). third grabs initially getting on the interstate but as i continue to accelerate my rpms go through the roof and it almost feels like im driving on ice. In the first 4 days for installing the trans 3rd has hooked no problem on the interstate twice and has spun twice. So i take back roads now to save fuel and reduce engine stress. Lastly some mornings it has stalled when accelerating from a dead stop within the first 1-2 miles of driving (lettin truck warm for about 5-10 min). Converter? Check ball? sorry for it being long winded just need to put all my information out there.

*if theres a better place for this to be posted please let me know

The stalling issue sounds more like a carburetor issue more then a trans problem (Just got to war, it up).

As for your your slipping in 3rd, I'd try using some Lucas Stop Slip (It worked wonders on the 330k original TH700r4 in my Suburban). It would probably buy you a lot of time, but to fix it properly, I'd replace the 2-3 clutch pack.

To me Automatic Transmissions are still horrendously complicated; anyone ever heard of the Turbo Encapulator?

xc_hide_links_from_guests_guests_error_hide_media

 

[Josh Helm]

I second the Lucas oil ... I have had good luck with the product as well ...

 

[1973c10]

Welcome

 

[78Scottsdale]

(Update- got on the freeway this morning and it hooked up just fine, only stalled once leaving my driveway). Ill try the Lucas product, as far as the stalling caused by the carb ill take a look at it but the stalling issue didnt arise until after the transmission swap. But hey fix one thing and another goes wrong wouldnt be surprising. hah thank you for your input

 

[TubeTruck]

Sounded like the intro to a support group. lol

That's what I thought too



Hi Jacob with transmission problems

 

[78Scottsdale]

Do you know how long it sat before you bought it? Maybe some dried seals and as it warms up and the fluid gets thinner the fluid is able to get around the drum seals and the clutch piston grip fades away. It might be worth a try to use Auto Trans Conditioner. They do help many times in a situation where it has sat for a long period of time. If the trans conditioner can soften the seals and that's the problem it should only get better and better with more driving and warming the seals.

The other thing that can happen, is the seals stick to the drum instead of slide with the piston. If they're stuck badly, and that piston does move then it's possible to damage the seals and there is no correcting that without a rebuild.

I have noticed the more i drive it the stalling issue has slowly subsided, but the problem with 3rd is still intermittent. Is there anyway to diagnose the seal getting stuck to the drum?