[Maniac]

I've had trouble with my tranny pan leaking, even after 2 gasket replacements. I've cleaned the mating surfaces, used gasket seal on both sides, and tightened the bolts down in a criss cross pattern. I'm wondering if the the surface on the tranny pan is warped in some way or not. I'm thinking of using studs instead of bolts, so I'll know that the gasket is getting lined up properly. Are the oil pan bolts the same as the tranny pan bolts on a 400/Th-400? 69' Catalina. If so I can just use a oil pan stud kit for the transmission. Any help is appreciated.

[Maniac]

I've had trouble with my tranny pan leaking, even after 2 gasket replacements. I've cleaned the mating surfaces, used gasket seal on both sides, and tightened the bolts down in a criss cross pattern. I'm wondering if the the surface on the tranny pan is warped in some way or not. I'm thinking of using studs instead of bolts, so I'll know that the gasket is getting lined up properly. Are the oil pan bolts the same as the tranny pan bolts on a 400/Th-400? 69' Catalina. If so I can just use a oil pan stud kit for the transmission. Any help is appreciated.

[sscherin]

Are you sure it's the pan??

other possible leaks that could look like the pan are the dip stick tube, detent shaft, kickdown connection and the cooler lines..

If you are sure it's the pan I'd take it off and see how flat the pan rail is.. If they are dimpled twords the case it'll never seal correctly.

If so take a ball peen hammer and gently tap the pan rails flat again on a block of wood.

To be sure the pan rails are extra clean I wipe them down with eiter starting fluid or thinner.
Just remember, no open flames [img]/infopop/emoticons/icon_smile.gif[/img]

Also.. dump the sealer. My TH-400 seald up much better with just a dry cork gasket.

[Goatman]

What material does your oil pan consist of? I have heard several people experience a porosity problem on aftermarket cast aluminum pans, such as the TCI deep pan. That may be it, if your pan is aluminum.

[Maniac]

I've got the stock pan. I had a quick question. Why is there a raised section in the middle on the mating surface of the tranny pan? Wouldn't it seem more logical to have two completely flat surfaces?

[Tim Corcoran]

Send a picture of that

[lust4speed]

I bet he is referring to the middle protrusion in the sealing surface that runs the length around the pan. It is an attempt at locking the gasket in place by crimping the gasket early in the tightening sequence so the gasket would be less likely to squeeze out. It also proves pretty good at separating the gasket in two strips if the bolts are overtightened.

My money is on one of the other seals/O-rings leaking and running down to the pan mating surface. One of the most overlooked leaks is the shifter rod seal. It takes a special tool to extract and install it. Seems a lot of shops ignore replacing this seal on a normal rebuild.

[Formulajones]

I'm betting since it's a stock pan we are talking about a sheet metal pan.

The trick to getting those to seal is to take a close look at all the bolt holes. 9 times out of 10 after decades of use and overtightening the bolts, you'll find those holes are mushroomed towards the inside (towards the trans) So now when your bolts are tightened the bolts bottom out before the pan gets a good gasket crush. I see this all the time.

The solution is to support the pan rail in what ever means you find available, and use a tapered punch that fits through the bolt holes, and give each of them a good whack so the bolt holes protrude towards the outside of the pan. Now when you install it, snugging up the bolts, it will crush the gasket for a good seal before the bolts bottom against the transmission pan rail.

This trick works with every sheet metal pan I've ever used with just a cheap basic cork gasket and no sealer. Generally after a couple of drives and heat soaks, I'll go back and recheck, and lightly snug the bolts as the cork tends to shrink a bit. After that it's good till the next service.

["QUICK-SILVER"]

Originally Posted by Tim Corcoran

Send a picture of that

That dude hasn't logged on or posted in 18 years.

Clay

[Formulajones]

Too bad it took 18 years to answer the poor guys question. lol

Still a good data point with good information that will come up the next time someone looks for a similar problem in the search feature, so not all is lost.

[ta man]

Hope the original poster wasn't waiting for an answer! If it was a cam question he would have had 10 different answers.

[poncho447]

Originally Posted by ta man

Hope the original poster wasn't waiting for an answer! If it was a cam question he would have had 10 different answers.

And two locked threads.

[lust4speed]

Whoops, but better late than never.

Well, maybe.