Transmission Pan Question

[Apoc Bane]

Nevermind, it looks like all these models are the same transmission.

Super Turbine 400 / THM400 / 3L80 / 3L80HD

Turbo-Hydramatic - Wikipedia, the free encyclopedia

 

[Barrman]

Sorry I jumped to the conclusion that you got it too tight. You very well could have it too loose. Put a regular 1/4" socket on there, hold the ratchet basically over the socket and see if using just your wrist you can snug the bolts up a little.

 

[Apoc Bane]

Sorry I jumped to the conclusion that you got it too tight. You very well could have it too loose. Put a regular 1/4" socket on there, hold the ratchet basically over the socket and see if using just your wrist you can snug the bolts up a little.

Oh no problem at all, I appreciate all the help you guys give. Without it be just my mind to wander.

I'll try putting a normal wrench/ratchet and see if I can snug any of the bolts any further.

I actually broke one off the first time I did it with the wrench, like you said would happen. That was when I was removing the pan to do the fix. Had to use a bolt out to get the broken bolt out.

 

[Apoc Bane]

Does it have to be a deep replacement pan ? or will a "standard" th400 pan work?

 

[Cucvnut]

to replace the pan you have now ?

 

[Apoc Bane]

to replace the pan you have now ?

Yes sir.

Functionality wise.

 

[Apoc Bane]

Forgive me if fleabay links are a no

Turbo TH 400 Aluminum Transmission Pan Alum Trans TH400 - eBay (item 200586153595 end time Mar-22-11 18:01:02 PDT)

 

[Cucvnut]

that will work.

 

[firecontrol86]

Not to hijack this thread, but about the "RTV only" comments, I did gasket only for my rear diff because it was leaking and now it's leaking again. It was a new diff cover too.

 

[rnd-motorsports]

firecontrol86 I have not used a diff cover gasket in many many years on everything that's comes into my shop on or off road clean surfaces and a small amount of ATV perfect just don't get carried away with the ATV never had a problem with leaks!! Make sure cover surface is flat!

 

[combat jump]

Apoc,

Did you complete the pan replace? What did you end up using to seal it? Any leaks?

2 weeks ago, I did a trans filter change and fluid flush. An old cork gasket came off in chunks. The new filter/gasket kit from Kragen/O'reily's had a rubber gasket. I installed it, and it dripped.

I think the problem was that the pan bolt holes had a kind of "dimple" to them - so that even with the pan snug under the bolts, the pan metal in between bolts lifted away from the surface of the transmission (and gasket) a bit; at least enough to allow a small leak.

I pulled the pan (had to rebuild the trans), got a master rebuild kit and it included a cork gasket. I had hoped for a rubber one, but did not want to re-use the leaky one as it had some creases from the previous installation.

I put the pan on a block of wood, and using two ball pein hammers (round side of one against the pan bolt hole) I tapped the deformed holes until flat. This was to make sure that the entire surface of the pan contacted the gasket and transmission surface when mated, and not just the pan bolt holes.

This time, I also applied some RTV black to the pan, then put down the gasket, and coated the top of that as well. Not too much. I torqued it all back together in a criss-cross pattern.

Yes, I have read some posts that RTV can get into the transmission and obstruct fluid in the valve body. I have also searched online to see what other transmission builders do, and have read enough examples of people using RTV on the pan, that I decided to do it.

The truck has been back on the road for two days, and nothing drips at all. I also replaced the rear main oil seal and oil pan gasket at the same time (a lot more RTV was used on that!) Again, I now have a clean driveway.

Whatever you decide, good luck and keep us posted on your results!