Opinions on RTV vs Gaskets on tranny pan.

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dwhip361

dwhip361

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Hey guys, trying to find out if anyone is using RTV instead of the gasket on the tranny pan. It seems like the gaskets always want to seep a little and I can't stand leaks. It also seems like alot of manufacturers are using RTV. If so, what type of RTV are you using? Thanks guys.
 
I use the vulcanized rubber gasket. RTV would squeeze all out to nothing left.
 
That's why they make transmission pan gaskets. To use them.
 
Get the good one from Mopar. The 727 gasket is # 2464324AC, the 904 gasket is # 4295875AC. It is nylon over steel with a molded in double silicone sealing bead. You do not put any goop on it. It can also be re-used. Around $25-$35 depending on where you get it.
 
69_340_GTS said:
Get the good one from Mopar. The 727 gasket is # 2464324AC, the 904 gasket is # 4295875AC. It is nylon over steel with a molded in double silicone sealing bead. You do not put any goop on it. It can also be re-used. Around $25-$35 depending on where you get it.
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Good advice....and not just reused, but reused for the rest of your life. Those things are badass.
 
Never use RTV on a transmission. Even a little bit of RTV that squeezed out can clog ports in the fluid passages.
 
You are correct that a lot of shops use RTV instead of a gasket, and that's fine on someone elses car for most transmissions.
The problem with doing it on TF's is that the pan rail on the trans has open area's along it and is one of the very hardest to seal up with RTV only.
Transmissions have filters for a reason, so clogging something up isn't really a concern at all.
I did transmission work for a living for quite some time, and I can tell you that we used RTV on most of them. (always used it on transmissions with a flat pan surface as it was company policy)
Everything got Dexron also as a company rule (unless otherwise requested or supplied by the vehicle owner.)
That being said, I wouldn't do on my own car because of the mess to clean up next time I took the pan off.

Just get the reusable gasket and be a lot happier when you never need another one. :)
 
69_340_GTS said:
Get the good one from Mopar. The 727 gasket is # 2464324AC, the 904 gasket is # 4295875AC. It is nylon over steel with a molded in double silicone sealing bead. You do not put any goop on it. It can also be re-used. Around $25-$35 depending on where you get it.
Click to expand...

I have switched to these on my TorqueFlights (two 727 and one 904). No leaks.
 
69_340_GTS said:
Get the good one from Mopar. The 727 gasket is # 2464324AC, the 904 gasket is # 4295875AC. It is nylon over steel with a molded in double silicone sealing bead. You do not put any goop on it. It can also be re-used. Around $25-$35 depending on where you get it.
Click to expand...

X2

I'm not sure about the factory part numbers, but the gaskets for the A518(727) and the A500(904) used the molded rubber(or silicone) style gaskets with the steel instert, as has GM and FORD. I was told by our gasket set supplier the reason they went to this type of gasket was to cut down on warranty claims for leaking pans on both the transmission and engine. We were told the gasket providing it was never bent, would allow you to remove the pan at least 5 times before you need to think about replacing it. Check in a 518 or 500 service manual and see what the pan bolt torque specs are as I think there were specific torque specs that had to be used. Also, make sure you've got the pan holes flat,they are not dimpled.

A lot of my customers would order this type of gasket, if available, instead of the usual cork or other material gaskets, dispite the added cost. Again, leaking pan gaskets mean you've got a warranty issue to fix.
 
I wouldn't use RTV either. I started using the Mopar molded gasket yrs. ago and haven't had even as much as a seep from a pan since.
 
no RTV, get a good gasket, and make sure the pan lip is flat and not warped from someone overtightening the bolts.
 
Thanks for all the replies everyone, I always used a gasket in the past but wondered if anyone used RTV. I see the answer was unanimous!
 
I had a badly warped pan (previous owner) I bought it with a bad leak. I couldn't get it to seal with anything. I tried RTV. RTV plus the gasket. Then I tried a really good steel core gasket and it still leaked. At that point I was ready to get a new pan. The old one was, for lack of a better word, f***ed. But I was determined. My friends father was a mechanic for years he told me about some stuff called The Right Stuff. Used it once, let it cure for a few hours to be safe. (It recomended 10 minutes If I recall) put fluid back in and it hasn't leaked a drop for 3 years. Its thick like tar, I've used it on seams on transfer cases too and as long as you clean it well it will seal anything. Used it on a friend's leaky intake gasket too. As far as I know he still hasn't replaced the gasket and it still doesn't leak.
 
alpha13 said:
I had a badly warped pan (previous owner) I bought it with a bad leak. I couldn't get it to seal with anything. I tried RTV. RTV plus the gasket. Then I tried a really good steel core gasket and it still leaked. At that point I was ready to get a new pan. The old one was, for lack of a better word, f***ed. But I was determined. My friends father was a mechanic for years he told me about some stuff called The Right Stuff. Used it once, let it cure for a few hours to be safe. (It recomended 10 minutes If I recall) put fluid back in and it hasn't leaked a drop for 3 years. Its thick like tar, I've used it on seams on transfer cases too and as long as you clean it well it will seal anything. Used it on a friend's leaky intake gasket too. As far as I know he still hasn't replaced the gasket and it still doesn't leak.
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got a cork one on, seems to be a small seeper, the trans. hasn`t even been put in gear yet !
 
I was a drivetrain tech at a Chrysler dealership. We used black RTV every day on transmission pans. You just have to be judicious with it - clean the pan rails very well both on the case and the pan, apply it evenly with your finger and be careful not to get it all over the place. Let it set for a minute and don't overtorque the bolts. If RTV was used previously, make sure to get the old stuff out of the bolt holes in the pan rail before putting the pan back on.

RTV stands for Room Temperature Vulcanizing which means it sets up quickly. The only way it would clog fluid passages is if you put it in there yourself. Of all the trans pans I had off (a lot) I never had one that had RTV in any of the valve body passages. You'd have to be really, really sloppy with it. Once it sets, it's set and it ain't going anywhere. It does not disintegrate over time otherwise you wouldn't be able to use it.

That being said, the Mopar molded rubber gasket is very good. Either that or RTV applied correctly will perform the same. I use one of those gaskets on my own 904 with a Summit deep pan and so far no leaks.
 
I picked up the Mopar gasket the other day. I have to say,that's the best gasket I've ever used! Not a single drop leaked, $21 at the dealer. I replaced the selector shaft seal also. Thanks for all the input guys.
 
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