TH350 Casing swap?

[Hillbillydrums]

About a year ago my dad and i broke off 2 bolts from the tranny pan into the trans. Dont ask how. We had some extractors with no luck. Ended up drilling and tapping right next to the hole and drilling a new hole in the pan. Tried gaskets and tried rtv. Wont seal. It wont leak for 2 weeks, then one night itll be all over the floor.

ANYWAYS
I have a parts truck and the tranny needs rebuilding. But how hard would it be to take the casing around the tranny and put it on mine? so now i dont have broken bolts and extra holes? My trans is great and shifts great and i really dont want to buy a new one or rebuild the other, unless its a must.
Would this swap be too much? Ive never played with tranny stuff, just motors.
Thanks in advance.

[roundhouse]

I'd try using the Toyota gasket sealant

Drop the pan and let it sit for a couple of days to finish dripping
Use some brake clean or something to get all the oil off
I use a rag with gasoline on it but you have to be careful with that

Put the sealer on and let it get tacky, then put the pan on but don't tighten it down , just run the bolts about half way in and let it dry for a day or two , then tighten the bolts the rest of the way

You could have some other issues like a crack in the transmission or something

But if you have get it rebuilt a TH 350 I'd probably the cheapest auto Trans to have rebuilt
To just swap all your guts into another housing

Most 4 speed autos are $2000
Some later model transmissions are $3200-3500 to have rebuilt


Sent from my iPhone using Tapatalk

[Magic1]

Had my th350 rebuilt and it was 500$ with a mild shift kit. Not sure if that's about average for that transmission or not because it's the first one I've had rebuilt.

[Irish_Alley]

i dont know why the rtv didnt hold, we use it on everything and it works great. did you use the cork gasket with the rtv or just rtv? i would use just rtv if i had to do it

[Hillbillydrums]

i dont know why the rtv didnt hold, we use it on everything and it works great. did you use the cork gasket with the rtv or just rtv? i would use just rtv if i had to do it

Just rtv. "the right stuff" to be exact.  Should that seal it up even with some messed up holes?
If so, walk me through the process. Maybe i just rushed it or missed a step.

[Irish_Alley]

make sure both surfaces are clean and use brake cleaner on a rag to make sure theres no oil on the mounting surfaces. put the rtv on the trans pan and let it start to get tacky then bolt her down

[roundhouse]

make sure both surfaces are clean and use brake cleaner on a rag to make sure theres no oil on the mounting surfaces. put the rtv on the trans pan and let it start to get tacky then bolt her down

Sometimes.   I ve found that tightening it almost all the way and letting it dry then finish tightning the bolts helps if it's a leaker

If you tighten them all the way before it dries it just forces the sealer totally out of the joint


Sent from my iPhone using Tapatalk

[jaredts]

I broke a bolt off in my old 350 and just left it out.  No rtv no extra tapped holes and it didn't leak a bit.  Is it possible That your new bolt hole is off center and not leaving enough surface for the gasket to seal against?  Have you checked the pan's gasket surface for flatness?  Is it possible that it is not even leaking from the pan?