Seeping 727 aluminum trans pan?

Posted By: Diplomat360

Seeping 727 aluminum trans pan? - 05/06/11 06:16 PM

Guys,

This is on my project car which has not seen any street miles yet.

I put on a TCI deep aluminum pan on my 727 a couple of years ago. I've noticed once before that the pan would start showing a very very slow 'leak'...more like a seep of trans fluid on the bottom of the pan. Over the winter as I put the car in the garage I cleaned up the pan, it was nice and dry, but over the few months I find that the bottom of the pan is now wet again.

I have examined the gasket area (pan to trans case) and see that there are no leaks there. The pan is actually nice and dry there, only the bottom is wet. There are no other leaks that I can find.

Has anyone else found their aluminum to be porous like that?

Posted By: Golden-Arm

Re: Seeping 727 aluminum trans pan? - 05/06/11 06:19 PM

you might be able to clean it, bake it to remove all traces of surface ol, and use an epoxy type sealant to coat the inside, to stop the seep. cast aluminum is porous to a small degree, and from piece to piece there will be variations. you might have been the unlucky guy, to get a porous pan. you dont want to seal it externally, just the inside surface, if it really bothers you.

Posted By: Anonymous

Re: Seeping 727 aluminum trans pan? - 05/06/11 06:23 PM

Sure it's not the gear selector seal?

It has a bad habit of dribbling down and making the pan gasket look like it's leaking.

Posted By: scratchnfotraction

Re: Seeping 727 aluminum trans pan? - 05/06/11 09:21 PM

Quote:

Sure it's not the gear selector seal?

It has a bad habit of dribbling down and making the pan gasket look like it's leaking.

the low/revs servo lever pin should be looked at real close also,the o-ring will seep to the pan rail/gasket.

I use brake clean to clean it good,air dry it with the airgun,then take a hand full of baby powder and throw on top of the shift lever seal area and let sit a while.

the baby powder shows the pink/wet spot

to pinpoint the leak

might as well check the dip stick tube o-ring and pivot pin all at the same time.

good luck

Posted By: RapidRobert

Re: Seeping 727 aluminum trans pan? - 05/06/11 09:23 PM

Quote:

then take a hand full of baby powder and throw on top of the shift lever seal area and let sit a while.

What was the trick/method posted the other day to get the baby fluid up there/spread even & it wasn't by hand

Posted By: Diplomat360

Re: Seeping 727 aluminum trans pan? - 05/06/11 09:30 PM

Guys, this is a rebuilt trans with 0 street miles. All new gaskets & seals. The vertical walls of the oil pan are dry...the seeping appears to occur just on the bottom of the pan.

I have not tried anything like the baby powder method, good call though...I will try this weekend.

Thanks!

Posted By: dOrk !

Re: Seeping 727 aluminum trans pan? - 05/06/11 09:48 PM

NEVER actually seen that "seeping" from the alum pan .. but I have heard of it. What does TCI say ?

Posted By: A12

Re: Seeping 727 aluminum trans pan? - 05/06/11 11:47 PM

My '68 rr leaked but only after I let it sit for a while. I changed pan gaskets three times, changed pans twice once from the stock pan to a deep MP pan with new gasket and then back to a new stock pan/gasket and still it leaked or at least I thought it was leaking. Tried the cork gasket, the standard thickness rubber gasket and a thicker rubber gasket and still it leaked. Found out it was that darn single O-ring around the dip stick tube where it enters the trans. With the converter full/warm and the oil level below that O-ring point no leaks let it sit for a short time and the fluid fills the pan and it raised to the O-ring/dip stick tube and it would creep along the pan and gasket area and make it look like the pan gasket was leaking. Check the dip stick tube O-ring seal, they rarely get changed and get hard and don't seal that well when they are old...

MikeR

Posted By: Diplomat360

Re: Seeping 727 aluminum trans pan? - 05/07/11 03:02 AM

Doc: TCI, reluctantly, after several emails to their tech-line suggested I send it back...this was last year though when I first noticed it, I really didn't feel like pulling it all apart as we were nearing a house move. Looks like I may have to bite the bullet this time around though.

A12: I switched to a Lokar flexible dipstick...it had a machined aluminum end, with an o-ring. To make sure it really wouldn't leak I also dabbed some Orange silicone around the opening (trans fluid safe), let it set and then filled the pan. No leak around that area what so ever...I can guarantee it...LOL!

Posted By: dOrk !

Re: Seeping 727 aluminum trans pan? - 05/07/11 04:54 AM

Dippy ...I would just try giving the INSIDE a couple of coats of GOOD QUALITY engine-enamel and then maybe BAKE the pan at say 350 for an hour or so.