How to install Transmission pan leak free!!!

I just want to here from everyone here how you put on a transmission pan gasket and have it not leak.
I have done this job a bunch of times with mixed results.
Sometimes it leaks and other times it doesn't.
I always use a sealant to glue the gasket to the transmission pan.
I normally don't use sealant to put the pan up to the transmission.

How do you do this and make sure it does not leak?
Is it possible that the gasket itself is not that good. I noticed most gaskets are very thin. How about Cork compared to paper?
What brand gasket is the best??

Thank you,
Rob
jerseysky66

 

Not saying this is wrong or right but its how an old Mechanic showed me, make sure the pan bolt holes are not pushed upward, lay the pan edge on a flat surface and take a ball peen hamer and tap the top gasket side of pan holes to depress if holes are domed up, if the gasket is rubber its more than likely folded to get it in the box, put it in a pail of hot water so it will lay flat, smear a layer of axle grease on pan gasket surface to hold gasket and install, overtightening is often why pan gaskets leak, if you see the gasket start to squeeze out the side it is tight enough, have done this for years and have yet had a gasket leak.as far as rubber vs cork, have had good luck with both, cork is harder to remove when its old and baked on.

 

ynotbuick, I will try and do this the way that you said. I may have over tightened the bolts the last time.

Jason, I am working on a 200r4 trans. Looks like it will be a big mess. I will see if I can find someones garbage can lid in this wind storm. I could not handle the smell of garbage in my so I went to garbage bags only:TU: I had the same problem with a TH-350 trans with the o-ring. I think I changed to trans gasket a couple times before I realized it was up higher :blast: :blast:

Thanks,
Rob
jerseysky66

 

Always do what ynotbuick suggested to insure the holes are knocked back down level or just below the sealing surface. Depending how overtorqued/distorted the pan is, this process can take some time. Once I think I have the sealing surface true. I take a fine flat file and run it over the sealing surface (parallel) to look for high or low spots. I continue to adjust using finesse with a hammer until they are all worked out. If you go too far, Reverse and knock it back.

Finally I draw-file the surface then smooth it with finer sandpaper so it is perfectly flat. Note: you should always run the file parallel with the sealing surface. I intentionally make the area right at the bolt hole just slightly lower (no more than 1/32") than the rest of the sealing surface because its going to push back up as the bolts are torqued, but not so much it will distort the gasket more at the bolts than anywhere else. The metal is not thick enough to prevent "slight" distortion when torqued to spec......IMO.

Make absolutely certain both the pan and tranny case are cleaned with solvent just before you install the pan. Oil has a tendency to drip slowly onto the surface so its best to let it drip dry over night. I know most instructions say not to use sealer but for 30 years, I always apply a "very" thin film of RTV on both sides of the gasket to seal any minor scratches or imperfections on the pan or tranny case as well as helping hold it in place during installation. I do this when using cork or rubber gaskets. I haven't found evidence where one gasket is better than the other. The condition of the sealing surface and method of application is far more important than cork or rubber IMO.

Always use a matched set of the special bolts with washer intended for use on the tranny pan. Do not mix/match bolt types.

As much as I like to think I can torque the bolts by feel, I always use an inch pound torque wrench on the tranny pan using a common criss-cross tightning technique. If you try to use the typical 1/2" drive torque wrench its too easy to over torque because the setting is so low.

When you are done, if all is well the gasket should not be mushed out at each bolt location more than anywhere else.

 

Thanks Jason,
I will spend some extra time on the trans pan and make sure it is flat. I like the idea with the file :bglasses:
Rob

 

:idea2: I agree with the above that the pan bolt holes need to be flat . A perfectly clean pan .

I "only" use permatex spray gasket adhesive on trannie gaskets . Unfold gasket , hang it up , spray . When the gasket is tacky to the touch set it on the pan and let it dry . Bolt it on gently , stagger the bolt holes , then go back and tighten the bolts a little more . No need to crank down on them . A 1/4 " rachet and socket can get 'em tight enough without bending the pan or distorting the gasket from over tightening . Clean and snug ...

PERMATEX SPRAY

Never had one leak ......:Brow:

 

Go to the home improvement store and pick up one of those plastic water catch trays that they make for washing machines. Their large, cheep, and great to have. I set two drain pans side by side (for front wheel drive cars) in the tray, removeing the bolts farthest away to the closest. Ive used the garbage can lid trick before, but it alwys seemed too small, and the tranny fluid catch trays for over your drain pan are too expensive for me. With the washing machine tray, it catches what the drain pans dont, and keeps the floor under the tranny clean. I hate laying in fluid pulling a motor or trans. These washing machine trays come in handy also when your draining your engine coolent, set your main bucket in the washing tray, aim for the bucket, and the tray will catch all those other dripps that the coolant runs off of. I think they cost from $10-$20, not too bad.

As for silicon sealer, I was alwys told never to use on an auto tranny. Because, a chunk could break loose and plug a port/ oraface. Now I do understand that most here at V8 Buick know better than to goop it up too much, just stating the ovvious for those that like to use too much sealer.

 

My cousin the mechanic told me to do what ynotbuick said to do. I forgot till I was all done and the fluid was in. It leaked. He's right.

 

A great solution to catching those under car fluids is one of those big concrete mixing tubs. I bought a couple of those to catch oil, trans fluid, and radiator fluid under the car. Holds 5 or 6 gallons, plenty for working on the old buick.

 

All done and no leaks :TU:

The instructions that came with the kit says to torque them down to 120 :rant:

I followed what was mentioned about making it tight enough so you can just see the gasket squeeze some.

Thanks,
Rob

 

:bglasses: :beers2:

 

The 120is inch pounds I always torque trans pans,I bought an aftermarket aluminum pan also ,liked the thick pan rails. No more leaks ever.

 

Hello I am new to this site and your thread is exactly what I am looking for.
My 1962 buick special has a transmission pan that is bolt free.
It had a solid rubber seal gasket? I can't find that gasket anywhere, everyone just tries to sell me a 22 bolt hole one.
If someone knows what I am talking about please let me know, and let know where I could find that solid gasket seal for my 1962 buick special transmission pan.

Thank you all!

 

Posting a photo of your bolt-free transmission pan might be a good idea :TU:

 

Tranny pans are always a challenge because of the lightweight oil in the system. The fluid is high-detergent machine oil, and tends to be 5-10W at best. Oil this thin is going to seep through gaskets eventually, no matter how perfect the mating surface or gasket quality. The steps above are important to mitigate the leaks & keep the pan & underside of the vehicle clean, but over time, you will eventually see some minimal seepage through the gaskets. I follow these steps all the time when doing fluid/filter changes, and I have yet to keep my tranny pan 100% leak-free.

 

I bought the Perfect trans pan. It's round, plastic, and sits on the floor in the garage right under the trans....

Seriously, I'm 0 for 2 on getting that thing to stop leaking.

 

Building on what others have said, I prefer a thick rubber gasket and I use a gasket glue (no RTV or thick sealer) to attach it to the flat pan flange. Make sure all of the edges of the holes in the transmission housing are flat (use a fie if needed as the edges sometmes pull down if the bolts are overtightened) and that the flange is as cean as posible. I torque the pan bolts to 60 inch-pounds in 3 steps while also cross tightening from one side to the other starting in the middle. I also retorque the bolts after the first drive.

 

I recently tossed my stock pan, it was leaking from the ghetto drain plug I tried to put on it, and all around the gasket.

Replaced it with the aluminum, stock depth pan from Summit Racing. That nice, thick cast rail made me feel a lot better. It came with a rubber gasket that would *probably* have been fine, but I tossed it in favor of a FelPro.

The FelPro gasket is pretty neat. The instructions say to install it bone dry, so I did. The holes in the gasket are undersized, so you can pop all the bolts through the gasket, and lift the whole pan-gasket-bolts assembly into place as once piece.

The bolts that came with the Summit pan were socket-head cap screws. I tightened them as tight as they wanted to go with a 3" allen key, and called it a day.

Haven't leaked a drop since.

~Mike
'66 Skylark 455-4

 

One of my trans pan bolts is snapped off, and I haven't bothered to get it out. The cast pan/FelPro gasket combo doesn't even leak there! :bla: