727 Tranny Pan Leaks... How To Stop?

[jim ritchie]

Most steel 727 pans leak because of over tightening,if you want to use the same pan,,clean well,,place on level surface and check all around with feeler gage for high or low spots and gently hammer so surface is even .Replace with new rubber or nylon gasket and a spot of lock tight on bolts and gently tighten all bolts ,a little at a time in cross pattern,I use a 1/4 inch drive and only turn with fingers or you can torque to specs but most wrench pullers get a feel for it,,but others think if it leaks,then just KEEP TIGHTENING! good luck,you'll get it

 

[440669superbee]

OK, what is the trick to stopping an automatic tranny pan from leaking? I started with a new chrome steel TCI pan with the supplied rubber gasket. I cleaned off both surfaces with wax and grease remover. I sprayed 3M adhesive on the pan side of the gasket as recommended by several fellow gear heads. I let the adhesive dry per the directions on the can. I cleaned all of the factory bolts and flat washers real good in solvent. I dried everything real good with a clean rag. I tightened the the bolts in a criss-cross pattern like you are supposed to. BUT THE S.O.B. STILL LEAKS. The bolts keep loosening and need re-tightened. Do I need to add lock washers or something?

I'm sorry.....I meant the shift shaft seal (not o-ring)....try saying that 5 times fast.

 

[beanhead]

It's tough with that aluminum housing and stamped steel pan, unless you have a really nice straight OE style pan it's tough... I switched to a Moroso aluminum pan with their blue gasket and that thing hasn't leaked a drop since... Of course 2 months after, it started leaking again but now it's coming from the selector shaft seal... that little turd's probably responsible for 90% of 727 leaks...

 

[twecomm]

Sure there will be many opinions on this, but.... I have a 66 Charger, 383, 727 Auto tranny 93K original miles. In spring when my car came out of winter storage, I drained transmission and put on a new pan gasket, replaced filter, fresh fluid. Not a cork gasket, but the pricey Mopar gasket described earlier in posts. Shortly there after, noticed a bit of tranny fluid on my garage floor. By a bit, I mean like a 1/2 teaspoon of fluid over the course of a week or so. Thought there must be some issue with the new pan gasket. Had car on a lift after the drips on the floor was discovered. No sign of leak anywhere at pan gasket, no leaking from convertor, but there was some evidence it was coming from somewhere about the front area of the transmission. Since it was such a minor leak and no other transmission issues, decided to try this Blue Devil transmission sealer. http://store.gobdp.com/transmission-sealer-00236/
Got a bottle at local auto parts store in March this year. Added per instructions, drove the 100 miles or so as directed, and leak solved ! It's now November, drove it a lot since spring and still not a drop on the floor. Had it on a lift last month and no evidence of a leak anywhere. Think the bottle was about $12.00. So, all I can tell you is it worked for me and my particular issue what ever it was...

 

[Billccm]

You are about the third, or fourth person that has good things to say about Blue Devil products. Thanks for the information.

 

[rumblefish360]

Did you use a torque wrench on the trans pan bolts?

 

[Rick62]

My buddy always said,"It's not a Mopar if it don't leak".

Or, if a t-flite isn't leaking it's empty!

 

[themechanic]

Sure way to stop the dreaded drip, drip, drip of the tranny fluid on your garage floor.

 

[mmissile]

I would take the chrome off the seal surface. Grind it, sand it whatever.

Ever scrape gasket sealer off of chrome? Thats right, it doesn’t stick to it. Thats why chrome covers usually leak.

This is your answer. Thermostat necks do the same thing. Get the chrome off the mating surfaces. Chrome parts, do not seal worth a damn.

 

[RT6PK]

OK, Thanks for all of the input. I went ahead and sanded the chrome off of the pan, bought one of the aforementioned o-ring gaskets, bought new pan bolts, cleaned the bolt holes, added one drop of loc-tite to each bolt, and torqued to the proper spec and in the proper sequence. Problem solved, no more leak. thanks again everyone.