Mopar Muscle Association UK

What is the best stuff to use to seal a trans pan gasket?
I've just lots several litres of trans fluid from a fast leak through the gasket area (on aTH400 ) .
Leaked so much it lost drive.
It was a new Felpro gasket, silicon one side to seal to the pan, then grease to the transmission face, so I could remove it without destroying gasket.
This clearly has not worked.
Grease side came back off cleanly with no damage, but I've wrecked the gasket trying to get it off the silicon side.
Is grease just going to allow the trans fluid a quick route out?

A couple of the bolt holes look to be previously over tightened which might be why it didn't seal as well.
I have dressed these back with a ball pein hammer now.

New gasket on its way, so what is the best stuff to put on the gasket faces to stop the horrendous leaks?
Hylomar both sides or something different?
Silicon I am wary of as it might clog the trans if any breaks off, but many car spares places only sell silicon now.

Transmission experts, what do you use?

No trans expert but Elring Curil-T works well when sticking the case halves together on a VW beetle engine
i.e metal to metal contact. no gasket and hot oil on the other side...trying its darndest to get thin enough the creep out everywhere...

works really well. not silicone based. more like a sticky putty once dry (but it never sets), stays where you put it.

don't get it on your best jumper....! doesn't come off

used it on case halves and oil pump housing which clamps in between the 2 case halves

its german so one presumes a range of german car makers use this and similar products.... gets used on turbo flange gaskets and everything

Dave

Hammer the pan flat and you should only need a gasket.

Blue just did mine when he fixed my gearbox, Dont know what he used but it doesnt leak a drop now. Sure he'll be along shortly.

I've never done anything other than dress the flange flat and secure the bolts with an inch lb torque wrench to the correct torque, no sealer and no particular type of gasket. Often you will have a leak from elsewhere that collects around the pan gasket to throw you off...

Sounds like a tidy flange is the key.

Always.

Just in case you still have a trans leak, I had a similar problem a few years ago changed gasket after gasket, flattened the pan flange, very carefully used sealant ( not recommended if it gets in the trans,.. ££££££) only to find it was the rubber o ring at the bottom of the dipstick tube had perished.

Just re-done mine due to leaking after using sealant. New Fel-pro gasket, clean both surfaces and de-grease, no sealer and tighten to 150 inch pounds with cheapo torque wrench from ebay - no leaks, results a good un.
As been said, check dipstick tube o-ring.