TH350, Rebuild or Not?

[StrongSurvivor]

Hi Everyone,

My '81 Z28 sat for eight years before I bought it. The previous owner tells me the trans, a TH350 was rebuilt shortly before parking the car. Should I rebuild or run it?

 

[CorkyE]

Run it, unless it was stored in a swamp.

 

[larrylarry]

Drive it see what it does. But be aware that there lip seals that must hold ATF at anywhere from 85 - 300 psi & when it sits for a long time the seals might leak then it won't shift for poo.

 

[Twisted_Metal]

Moisture in it will break down the clutch packs.
If it sat indoors it should be fine.

If it has a mushy feel to the shifts... It's time for a rebuild.
Warm it up, check the fluid level and run it to see what it does.

 

[StrongSurvivor]

Thanks everyone for your feedback. I'll run the trans as is, at least for now. Fingers crossed that it does the job. I've got enough to do as it is!

 

[tlcronk]

Some years ago when taking classes for rebuilding transmissions, I was told a little secret.
If the seals are dry from either sitting a long time or high mileage, just dump about 4 ounces of brake fluid in the filler tube.
Start it up, and shift the gears forward and back. Do this and let it warm up and try again.
It might take a day or two to soften the seals so they apply properly.
Just don't expect doing burnouts right from the get go. Give it time.
This suggestion was from my old time instructor. He worked for GM as an on the road rep./service guy back in the 50's-60's..
Fords were especially prone with their harsher fluid.

My $.02

 

[lapedr]

I rebuilt my th350 and I am not a trans expert I just made sure I followed step by step instructions, if you are going to rebuild it I have all the special tools needed and would sell them to you at a fair price, I dont need them anymore

 

[StrongSurvivor]

I rebuilt my th350 and I am not a trans expert I just made sure I followed step by step instructions, if you are going to rebuild it I have all the special tools needed and would sell them to you at a fair price, I dont need them anymore

I'm undecided about the rebuild. What special tools and how much? With shipping to 30656 please.

 

[lapedr]

There are special compressors bushing and bearing drivers I will look into a cost this weekend and get back to you I suggest you get a gm overhaul manual from the 70s it shows step by step with pics and spec tools I got one on amazon

 

[lapedr]

Below is a pic of the manual I used, it lists step by step from disassembly, to inspection, to replacement, to assembly. Also below is a pic of the special tools. I don't have all of the tools in the pic but I have what is needed to do the job. I can take a picture of what I have, and message it to you if you pm me your cell number, or post it here just let me know.