I have one of these on my car (no, I didn't put it on there...).. B&M Chrome TH400 Pan

I can not get this thing to seal. The shop who did the rebuild on my tranny said they could be tough. After puking tranny fluid constantly, I'm kind of done with it... Replacement suggestions?

Thanks in advance!
Drew

Just like all other trans pans, don't crank down on the bolts hard and it won't leak. A light smear of ultra RTV also helps.

Jeez. Never thought to loosen them. Guess I'll get a new gasket, make sure the pan isn't warped. Finger tighten until snug and let it sit for a day. From what I can find, the torque spec is 11ft/lbs. I'm way tighter than that now.

Thanks Chief.

Sometimes it's not the pan but leaking from somewhere else and collects at the pan gasket and tricks you. Suggest you thoroughly wipe it down and see if it's leaking from somewhere else. Mine was leaking at the shifter shaft seal which is common. The other place is the dipstick tube

Yes, I've always had a leak from the speedo-cable assembly at the trans. I've replaced the seals and nothing seems to work. Perhaps the speedo gear housing is bad?

re: pan leak; much like the engine oil pan, once it's over-torqued and distorted, you have to remove it and hammer out the deformed areas around the bolt holes. Even with a new gasket, there will be uneven compression on the seal surface. the bolt torque is critical and is the reason I always use a torque wrench.

I guess I'll go through all of it, with all the info here. It took me forever to find the torque specs for the pan... Can anyone confirm 11ft/lbs is correct? I generally pretty anal about torque specs.. Not sure why I wasn't in this case.

If it is bent, I will order a steel replacement, I won't try to pound it out.

Once i have it off, per Bob, I will wipe it all down, and put some masking tape on it. So I can see if it is leaking from above the pan gasket or at the pan gasket. If it is leaking for the shifter seal shaft, I am going to pretty angry. It was just rebuilt, and I think I'd have to pull the engine to get to that seal. That'd be the 3rd time this year it would come out.

Pete:
If it is bent, I will order a steel replacement, I won't try to pound it out. That never works out well for me. I did that on a Silverado, and it was fine for about 7 miles. Once it heated up, it cracked, and adios tranny fluid. That trip lasted about 2 more miles.. haha.. I actually replaced the Speedo housing b/c I had an issue with it leaking. I was missing the rubber seal that went between the speedo gear and housing. I couldn't find the seal anywhere.. so I just bought a whole new housing. Fixed that problem. I actually wrapped a white rag around it and went for a 2 mile drive, checked it, then a 5 mile drive and no leaks.

Again, thanks for the multitude of advice, I will employ all of it to get to the bottom of this.

11ft lbs sounds like to much(11in lbs maybe)? Especiallly for an aftermarket chome pan.
I use a 3/8 ratchet(one handed) and snug up every 3rd one trying to keep same pressure on each. Then go around next loose ones, then the rest of the loose ones. Then one more time on each one till all feel same tightness.

The torque specs are in the '68 Pontiac Service manual.

According to the 69 factory manual the pan to case torque: 12 ft/lbs. [M40 trans sect. 7E]
As with any pan style gasket, all surfaces have to be oil free. And, use a cross bolt torque pattern, making 2 passes.

BTW, I wasn't suggesting using an OMG big hammer. I have a hammer that's similar to a body hammer and back that up with an aluminum block.. Another technique is to use a pair of aluminum blocks and vice to press it back into submission. I have a vice with aluminum jaws, so it's quick & easy.

My suggestion is to replace with an aluminum pan. They are a little more expensive but they seal and also keep your transmission cooler.

Chrome anything rarely seals. The only way that I have gotten any chrome part to seal is to take my die grinder and a sanding disc to the sealing surface. This will create a sealing surface for the gasket to adhere to. Chrome transmission pans are the worst. Also, if the bolt holes are bowed up a little, which happens a lot due to over torquing, A wood block and a ball peen hammer will get the holes back to normal.

Good advice all around. Looks like the front of the pan is dented, and it throws the geometry off a bit. I checked all over the tranny housing, found no sign of ATF anywhere. It has to be coming out of the front of the pan where it is dented. I am going to order a shiny new chrome pan (kidding) and install with new gasket as suggested above. Thanks for the help and advice. I am 100% positive it is a pan issue.

Aluminum pan went in, installed to correct torque.. Amazingly enough.... It's not leaking. That's pretty typical, I generally get it right on the second or third attempt. haha
The difference in pan quality is night and day. What a piece of crap the old one was!

Thanks all for the advice!