Trans pan sealing

[steve from staten island]

I used the wrong product on my trans pan and its now leaking. Have a new gasket. When i was in the parts store we met a guy who was suppose to be a experienced engine builder who specializes in older cars. He told us what he uses on trans pan is, Clean all mating surfaces with brake cleaner and dry, must be perfectly clean. Use 3m weatherstripping(black stuff) on gasket to pan. Spray 3m copper spray a gasket on trans gasket itself. Put the pan on in one shot with out moving it around. Use two people if needed
Or should i just use 3M trans gasket sealant? What method do you use and thanks

 

[Demonic]

I usually check the pan and trans case with a straightedge. Pans are often distorted, pulled up around the bolt holes. Support the pan if you need to tap the flange straight. I use the cork gaskets, and a paper thin coat of UltraBlue Permatex on the pan side. Do not over-torque the bolts.

 

[miller]

I've always used CopperKote on mine. Spray, or brush, and nothing else. Make sure the pan flange is straight.

 

[BeeKool]

I always use the Permatex Black. Place the bolts in an alternating pattern and just snug them to start. Return 12 hours later and properly torque them.
I don't doubt the fellow you spoke with is correct, especially if the pans are older and slightly warped.

 

[Charrlie_S]

I don't know about the 727, but on the 904, I use the new style Mopar reusable gaskets. No sealer required, or desired.

 

[65-440]

I use the thick molded rubber/ reusable gasket off the later model ram / Dakota pickups on all mine with zero leaks And zero extra sealer ..... but, like others have stated you must make sure the pan rail is straight as possible
https://www.amazon.com/Mopar-0246-4324AC-Trans-Gasket/dp/B0046NPNMW

 

[dvw]

I use no sealer. Tighten with a nut driver only. Many pan leaks are incorrectly diagnosed. Rear servo pin, fill tube, valve body/kickdown seals, cooler lines, and tail shaft gasket are all above the pan rail. If it still leaks after gasket replacement, clean it with brake clean. Blow dry with compressed air. Then dust some baby powder on the trans. Let it set and look for the powder to turn dark indicating the leak area.
Doug

 

[493 Mike]

I've been rebuilding transmissions for 47 years now and over that time I never used anything but the gasket to seal the pan. I set the turned down edge of the pan on my vise and tap down any deformed bolt holes and use the "feel torque" method for securing. I will say I have had a few leak but, using a different type of gasket always solved the issue ( there are many materials used in pan gaskets ). I do like the new silicone material though.
Mike

 

[Ski 61701]

I use the fel pro or napa brand gasket. Its a rubber like texture but isn't rubber. No sealer is needed and as long as your pan is straight, and you torque it down evenly, no leaks. Best part is when it comes time to drop the pan, no scraping just a shot of brake clean on the surfaces and put a new gasket on. No leaks at all and the gaskets are cheap.

 

[SublimeSixpack]

I've been using these for the last few years, comes as a kit. After filter change I clean surfaces then install gasket and pan. No sealer.

 

[RT K_line]

I'v rebuilt many transmissions in my career and have always used the cork gaskets available from the trans parts houses with no sealer. But now I would use the newer gasket available now that 65 440 shows in his link. But I also agree with previously stated that most pan gasket leaks are coming from somewhere else.

 

[pwDave]

I used the wrong product on my trans pan and its now leaking. Have a new gasket. When i was in the parts store we met a guy who was suppose to be a experienced engine builder who specializes in older cars. He told us what he uses on trans pan is, Clean all mating surfaces with brake cleaner and dry, must be perfectly clean. Use 3m weatherstripping(black stuff) on gasket to pan. Spray 3m copper spray a gasket on trans gasket itself. Put the pan on in one shot with out moving it around. Use two people if needed
Or should i just use 3M trans gasket sealant? What method do you use and thanks

65-440 is using the right one, when I bought one I bitched and griped about the price, but, the trans has not leaked a drop in 5 mo.s, I am tickled!! I had to give 41.00 for mine. Dave.

 

[Shorthorse]

As mentioned before, pan flanges get distorted at the bolt holes from improper tightening. Has anyone ever used these? Seems like they would distribute the tightening force more evenly and protect the holes and flange.

AR Engineering, $45.

 

[conv67bdere]

I've a;ways been told NOT to use RTV or silicon type materials on the transmission pan as the transmission fluid eats through the stuff and can cause the dislodged material to get into the trans and possibly clog up the ports . . .

I've always used a standard gasket and make sure that you tighten it down in small increments ( with a torque wrench ) until you reach the desired torque setting . . .

Good luck ! !

 

[YY1]

I bought a silicone gasket for my 904 off ebay.

$40 IIRC but it works perfect. No sealer required.

 

[mopar73dge]

I was told not to use sealer on a Trans gasket, a very good quality gasket and a retighten of the bolts after a few weeks will stop 98 % leaking issues.
Recheck every year if you have some seepage, they do loosen up sometimes.

 

[YY1]

https://www.ebay.com/itm/CHRYSLER-M...ash=item41b1a6ad9c:g:Gn0AAOSw3YNXXtzR&vxp=mtr

 

[Tori]

I don't know about the 727, but on the 904, I use the new style Mopar reusable gaskets. No sealer required, or desired.

That's what i did with my 904, can't get the damn thing to seal. Even torqued to the proper torque.

 

[493 Mike]

That's what i did with my 904, can't get the damn thing to seal. Even torqued to the proper torque.

Did you flatten the holes in the pan which could have been distorted by prior over tightening?
Mike

 

[Tori]

Did you flatten the holes in the pan which could have been distorted by prior over tightening?
Mike

I did. Didn't think to put a straight edge on it though so will do that when i deal with it next. I need to deal with a leak at the shift shaft seal first and see how much effect that has on my leak. I know the pan is leaking though because it will leak just sitting still for a few days.