best way to seal transmission

[gr868]

i seem to have bad luck with transmission pan gaskets what's the best gasket or goop you guys have used?

[critter]

On my TH400 I've always used a paper or cork gasket and never had a problem. The key for me was paying attention to the proper torque on the bolts and making sure the pan flange was flat.

[gr868]

do you know the torque specs by chance?

[critter]

I don't have my service manual with me here but I remember it being something like 12 ft. lbs. It's not much. Over torquing is one of the most common ways to create leaks.

Some also say to use "the right stuff" sealant on it. I've never had to. Get the flanges on the pan flat, torque it down easy in a criss-cross pattern it it will seal.

One other little tidbit. I found that a persistent leak I had was not the pan. The slip yoke on my Pontiac had a pressed in plug under the U-joint. It was leaking around the plug. I sealed it with JB Weld and never had another leak from there.

[parsonsj]

Some also say to use "the right stuff" sealant on it. I've never had to. Get the flanges on the pan flat, torque it down easy in a criss-cross pattern it it will seal.

Exactly. I've probably installed 200 drain pans on transmissions. Flat flange, good quality cork gasket, proper torque, correct tightening sequence. It'll work.

jp

[gr868]

ok hopefully with those tips it will seal i went through the trouble of getting an aluiminum pan to seal better so i think that will help thanks for the tips i just had a new transmission built because my old one leaked!!

[vintageracer]

Pour a little brake fluid in the transmission. Not much, just a little.

It will seal your leak quickly. Works great!

[gr868]

i did that along time ago on a power steering pump worked great but in a brand new trans i would be hesitant!

[MonzaRacer]

no cork no cork n o cork.
Get the felcoprene gasket from NAPA, get some 3M black weather strip adhesive, clean both pan and trans till dry, glue gasket to pan flip over onto something flat for few minutes, not too long just so weather strip sets some and gasket wont slide.
Get some carb cleaner and wipe trans down , no fluid on gasket area. never never never use silicone or as some kits recommend grease to install a gasket.
Bolt pan up and torque to spec, the rubber felcoprene gasket can be watched as bolts are tightened just needs small amount of squish. Then it should be fine too tight and you can split gasket.
Cork is junk on trannys and oil pans anymore, had my share of issue with it heck I even use thick NAPA rubber valve cover gaskets.
Brake fluid is an old used car trick and needs to be repeated every 6month or so its also only patch.

[vintageracer]

Brake fluid is an old used car trick and needs to be repeated every 6month or so its also only patch.

But is sure does WORK GREAT!!!!

[gr868]

aluminum pan rubber gasket and anerobic sealant did the trick thanks guys!