egertge

i have no idea what to try next. ive tried 8 times to get this thing to seal, but it just wont do it, ive tried just a rubber gasket, rubber and blue rvt silicone, just silicone, and cork. ive tried each a few times. ive also flattened the pan out where the bolts go through, torqued the bolts properly, and tried numerous tightening patterns. what am i doing wrong? this last time was one of the better ones, it is just leaking in the front, especially around the front passenger side corner where there is no bolt right on the corner. its a th 350. would getting a new pan help matters? is there a better gasket than cork? ive had a little better luck with cork rather than the rubber. i am out of ideas and am about ready to start kicking the thing after getting this frustrated with a stupid gasket :banghead: :mad . i tried rubber gasket and silicone last week, let it set for a week before putting the atf in, and it was one of the worse leaks yet, a steady drip out the front. any advice would be greatly appreciated.

Top_Notch

Are you sure the mounting flange on the pan is straight? If so, use a rubber/neoprene gasket and just snug the bolts following the torqueing sequence. I've literally done hundreds of these and never had a problem.

If it is still leaking, make sure it's the pan gasket and not something else.

Stewart's74

Mine leaks a bit too. It's like the Vette is marking its territory.
If you get it to seal, let me know :smash:

The_Dude

When I did the th400 in my caddy, I used the cork gasket that came with the filter kit, no sealer, and torqued in steps and in sequence. I didn't have any leaks. If I were you, I'd probably just get a different pan. Good luck.

mrvette

IMO, if nothing else works,....of course check everything above that pan...and there is a TON of seals and junk up there, from the front pump to the converter seals....yes there are two...and also the shift linkage and the dipstick tube...I had one once that I SWORE more than once was that damn pan....NO,....it was the dipstick tube, incidious as hell, sneakey dirty MF'er it was....#$%^&()!@%$^#_

GENE

BigBadRed

I have never been able to get a gm pan to seal. Mopars, yes. Fords, yes. But never a gm. We had to change the tranny fluid in my wifes firebird. I told her I would guide her or take it to the shop (which we only do if there is no way we can do it ourselves) There was no way I was going to do it. She has done more then a few projects on the cars herself so she said she would go ahead and try it. Poor girl did not notice that although all the bolts were ready to come off the pan, it would not drop straight down do to interference and had to come out at about a 20 degree angle. Well she removed all the bolts dropped the pan straignt down, it caught and dumped about 3 quarts of tranny fluid all over her. I would have laughed, but I know if I had done it, the exact same thing would have happened to me. Anyway, she cleans it all up, used minimul rtv per the instructions that came with the new filter and gasket and the MF'r does NOT leak. I have failed at LEAST 10 times on gm pans. She gets it on the first try. :yesnod: :cheers: :rant:

mrvette

BBOrange, If it was ME and MY wife....snicker,...we'd be laughing to this day over that, wifey-poo has a can doo attitude..and will if asked, jump in over hear head...so to speak....

GENE

midwest-vette

Two comments - I use cork and this stuff called Indian Head, it comes in a little brown bottle probably 5 ounces and has a picture of an Indian on it. The stuff is sticky as hell. I put a small bit over the pan where the gasket sits, let it get almost dry and then install the pan to the tranny. The gasket never moves. It doesn't break down over time, last longer than the gaskets.

Second thing: As someone mentioned, the dipstick tube can seep fluid and make it look as if the gasket is soaked and puking fluid. You might dry the area real well, take a drive, and check they area with a mirror. PepBoys sell similar sized rubber 0-rings if you need to replace it.

page62

Gotta go with the consensus. Transmissions can leak in a dozen different places! :yesnod:

egertge

im perty sure it is the pan. where would the leak be if it was the dip stick? this last time i did the cork gasket, i put in two quarts and went under the car to take a look, no leaks, so i put in a third, slid back under the car, and watched the cork soak with tranny fluid then a slow drip in this one spot, so im perty sure it is the seal. it was right by the bolt that is on the front edge. farthest to the passenger side, that is the only place it leaks usually, so maybe there is something else above it that leaks and makes it appear that the pan is leaking there? i cleaned both sufaces, then put the pan up and held it in place with a couple bolts barely in, then made sure the gasket was lined up correctly. im still not real sure about the bolt sequence to go with for tightening. i get the inside out method on valve covers, because they are a rectangle, but what about the square pan? i tighten all the middle bolts in a criss cross kind of pattern, then do the corner bolts last. is that right? thanks for the advice, keep it coming.

mark79,80

Had a similar problem on my turbo 350. Thought it was the pan gasket but
eventually found that the selector shaft seal was leaking. The fluid ran
down around the edge of the pan making it appear that it was leaking.
The selector shaft seal can be changed by removing the linkage and prying
out the old seal with an ice pick. Be careful not to gouge the selector
shaft or it will have to be replaced. The new seal can be installed by
pushing it over the selector shaft and using a long socket tapped with a
hammer to drive it in place.

macx

I'm a recent "returnee" to GM so don't have any hands on w/the later model trans, but if you ever do get it to seal initially, I always use the following trick to make sure it STAYS sealed. Clean the bolts and bolt holes (I just use carb spray) then blow the bolts dry and holes dry with comp air, or let air dry well. Use a dab of loctite on the bolts (threads must be clean & dry), use the factory torque & sequence, and it will never come loose over time.

8T1-7T9 BIONIC VETTE

I watched a guy in the hobby shop put a trans pan on and he was tightening the bolts with a socket wrench. I asked him how does he know he has the correct torq.....he said I snugged it down good and that should be fine....later I watched him put the trans fluid in and the leaks started.....So I could hear him cusing......Not wanting to be a nosey sort of guy.....I told him he would have to buy a new gasket....he said he'll drain it again and use sealant the next time using the same gasket and socket wrench.....So I watched as he filled her up again.....leaks started instantly.... trying not to be a know it all.....I told him he needed a new gasket because he deformed the last one......and use a good calibrated torq wrench next time.....He went out and got a new gasket and torqued to spec's......No leaks.....end of story. Life's a bitch...... :D :flag :seeya

79VetteMike

Check your fluid lines. There are couplers that screw into the trans and your lines screw into the couplers. If you don't use line wrenches on those, they will most likely leak.

egertge

with all this adivice, i think ill have to roll under the car tomorrow and check for other sources of leaking. i havent drained it again yet, just have a drain pan under it to catch the dripping right now. so what is the best way to tell if it is coming from somewhere else other than the seal? the only place it is leaking is in the front, so what other seals are located there that i should check? the sides and back are bone dry still, so im thinking everything is ok back there. im gonna kick myself if it does turn out not to be the pan gasket. lots of wasted hours and gaskets if that wasnt the problem. oh well, live and learn, that seems to be the way it goes with this car.

Buffalo Dude

:withstupid:

Gary79

never had this much of a problem with trans pans as you seem to be having. the trans guys around here say cork or rubber are okay, the important thing is DON'T over torque, DON'T use RTV or anything else(you don't want a small bit of this breaking off and clogging up one of the small passages in the tranny, do we?), DO get the pan straight and clean, and clean the edges of the tranny with a solvent, wipe dry. good luck

ravenlunatic

Clean everything really good then use a UV dye thats compatble with ATF, it will show the source of your leak. Good Luck!

8T1-7T9 BIONIC VETTE

:iagree:

Matt Gruber

crazy idea?
if you do pull the pan again, see if you can squeeze a small flashlight in the pan with no gasket. then inspect the crack to see if it is wider than it should be, also look for a crack/gouge in the trans sealing surface.
On a M/T valve cover, cast, it was cast wrong and i had to fill in a void with JB Weld.

One time i thought it had a bad front seal, and it was the rear main seal :mad