Can I Combine a Cork Gasket with RTV?

[rangerenthiusiast]

Hey, all.

I’m thinking about putting a thin film of black RTV on both sides of the cork gasket going on the auto transmission pan of my 1992 Ranger with the A4LD. I’ve always used cork gaskets and never had one leak before, but I’d like to have a little bit of extra insurance on this one, in case there are any devisions from absolute flat on the pan (thus, the RTV).

I feel like a long time ago, someone may have told me to use either cork or RTV, but not both. There was never an explanation why and I’m starting to wonder if I imagined it.

Thoughts? Thanks.

 

[Dirtman]

You can... But it's pointless and just makes the next time you remove the pan more of a pain in the ass. Use a gasket or RTV, not both. Only time you would want RTV and a gasket is on multi peice gaskets to seal the joints. A quality gasket and applying even torque in a proper sequence is all you need for a good seal.

There are also re-useable rubber & steel bonded gaskets available for that trans. They are the best thing since sliced bread. I've re-used mine 6 times so far and it still seals dry as a bone.

 

[RonD]

Cork gaskets swell with fluid contact which makes them work well as trans pan gaskets, or valve cover and oil pan gaskets.

But they are not reusable after a few months of use.

I have used RTV to hold cork gaskets in place, not really for sealing the gasket.

You need to be careful with RTV in that when you tighten the bolts the RTV will be squeezed out, and on the inside of gasket it can come off in little balls that can clog screens and filters
So use sparingly

 

[Transman304]

Why not use a (fiber)duraprene gasket?

 

[adsm08]

Why use a gasket at all? Oil and ATF leaks protect the underside from the elements.

 

[Transman304]

Why use a gasket at all? Oil and ATF leaks protect the underside from the elements.

 

[rangerenthiusiast]

Why use a gasket at all? Oil and ATF leaks protect the underside from the elements.

Dad? Is that you??

 

[rangerenthiusiast]

Why not use a (fiber)duraprene gasket?
View attachment 24708

That looks like cork to me. What’s the diff?

 

[Transman304]

It’s a fiber compound that won’t squish out like cork. More forgiving than cork on torque. You can spray with high tack or shellac. I use them dry and have been for 30 years with no problems.

 

[Shran]

Not a fan of cork gaskets at all. Knowing what I know now, I wouldn't use RTV with them either... especially on a transmission... although I will admit to using both together in the past.

My trick with gaskets is to smear just a little dab of grease on both sides so that it sticks to whatever you're applying it to... this is especially helpful with transmission pans and oil pans, keeps it from moving around when you're putting bolts back in.

 

[Dirtman]

My trick with gaskets is to smear just a little dab of grease on both sides so that it sticks to whatever you're applying it to... this is especially helpful with transmission pans and oil pans, keeps it from moving around when you're putting bolts back in.

High tack is great for oil/water gaskets for this purpose, or grease but its not as effective as high tack... I may be a stickler here but I never mix anything that will touch ATF. It takes nothing to contaminate and eff up ATF.

12 Quarts of ATF can go from non functioning, to completely perefect with 2 ounces of additive. Think some grease wont do the opposite?

 

[rangerenthiusiast]

Not a fan of cork gaskets at all. Knowing what I know now, I wouldn't use RTV with them either... especially on a transmission... although I will admit to using both together in the past.

My trick with gaskets is to smear just a little dab of grease on both sides so that it sticks to whatever you're applying it to... this is especially helpful with transmission pans and oil pans, keeps it from moving around when you're putting bolts back in.

Yeah, I’ve used a touch of white lithium grease on them in the past. Never got into using the high tack spray-a-gasket with them though (always seemed messy and unnecessary). I asked about a light coating of RTV because I’ve always wanted to try it, but also worried about bits of it breaking loose and making their way into bad places. I’ve never had a cork gasket leak in over 30 years, but the few times I’ve used rubber (especially those half-cork/half rubber abominations that my ’86 F-150 used on the oil pan of the crappy 300 ci), they always have. Can’t stand the things.

 

[Uncle Gump]

I don't believe I've used anything on the trans pan... but the gasket.

I do however always check the pan bolt holes for flatness. Seems like 75% of them have been over torqued. I typically straighten the bolt holes with two ball pein hammers on the edge of my workbench.

 

[Shran]

Think some grease wont do the opposite?

Nah... we are talking about a couple small dabs, just enough to wet the tip of your finger, smeared around the gasket. There might be a tiny, tiny bit that gets squished out and mixed with the trans fluid but not enough to matter.

High tack does do the same thing but then you gotta have it on hand when you're doing the gasket job... I probably have a can of it somewhere, maybe, but I KNOW there's a few tubs of grease in the shop at all times, just happens to be what I use since it's handy and works well.

 

[rangerenthiusiast]

Nah... we are talking about a couple small dabs, just enough to wet the tip of your finger, smeared around the gasket. There might be a tiny, tiny bit that gets squished out and mixed with the trans fluid but not enough to matter.

High tack does do the same thing but then you gotta have it on hand when you're doing the gasket job... I probably have a can of it somewhere, maybe, but I KNOW there's a few tubs of grease in the shop at all times, just happens to be what I use since it's handy and works well.

Right on!