Trans pan gasket..sealer or no sealer?? and other trans ???

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cosgig

cosgig

MoBro Inc.
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OK all, I'm looking for some informed opinions about this subject. I am doing a trans filter and gasket change on the 66 convertible and I am going to use the gasket that came in the filter/gasket package. Should I use any sealer on the gasket before I put it back together??

A little background... When I got the car and drove it up on the trailer, the trans was "squealing", making a noise that sounded like a band slipping or something. I drove it off the trailer and around the block, and when pushed it would squeal, but shifted through the gears under light pressure without making a noise. I figured a filter and gasket change would be in order to remove any burnt fluid and see whats going on in there. I am not sure this is going to fix that squealing, and may have to go back in for what?? I don't know. I'm not a trans guy and am not sure if any adjustment is done inside the pan and don't want to seal it up and have to go right back in, hence my question. I guess if anybody can shed some light on the adjustment of the bands also that would be a great help. There looks to be an adjustment inside the pan and I'm not sure what it adjusts.

Also, I'd like to get any opinions on what trans fluid everybody is using for these old cars. I hear a lot of people are using the old type "F" fluid and to stay away from Dextron. Any help would be greatly appreciated. Thanks all for your time!!! Geof
 

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i dont think u want to use gasket/silicon sealant. as when it squishes together u dont want the excess to go in the pan/transmission oil.

i use ATF-4. type F is kinda old school. ill have to check my tranny book to see what u need for adjustments.
 
There are sealers out there for the tranny anaerobic I think but if both surfaces are true and flat you should never need any sealants.
 
I always use a light coat of Permatex sealant on both sides of the gasket.Brush on or the spray on work real well.

Jim
 
As Snake said, if the surfaces are true there's no need for sealer. As for the adjustment, that's the rear band adjustment. Most are single wrap rear bands that are torqued to 72 inch lbs. then backed off 2 turns. If it's a double wrap band they are adjusted to 72 inch lbs. then backed off 4 turns. Don't forget to adjust the front band too (the adjustment is on the outside of the case above the shift linkage). It's adjustment is really more critical than the rear band because the rear band is only used in manual low and reverse while the front band is for 2nd gear application. Never had a trans. squeal. Are you sure it's the trans? Are the belts tight? That's the only thing I've ever had squeal. No reason at all to not use Dexron. Whoever told you to stay away from it don't know squat. Using type F is an old trick that made them shift a little firmer.

BTW: if the fluid is burned the trans. probably won't last long. Was there much "mud" (friction material) or metal in the pan?
 
Cometic makes a gasket that is slightly thicker than stock, they seal great (assuming your pan is flat), and you can resuse them multiple times if necessary.

In my Torqflites I've always used Dextron/Mercon and never had any issues. As noted earlier, Type F is what we used many years ago, but of the guys I know that build transmissions they say avoid Type F and use D/M.

S
 
What... only 6 replies in one night?? I'm a little disappointed in you guys!!!!LOL!! Oops, wrong thread!!!LOL!!

Hey, thanks for all the replies guys!! Fishy, there was some sludge in the bottom of the pan but not too bad, and someone who had been in there before had put a magnet in the corner that was covered in a sludgy substance that must've been magnetic cause it was a bear to get off, even in the dunk tank. The fluid did not smell burnt at all, although when wiping everything clean and removing the filter revealed black flakes congealed under the filter. I put a small clump between my fingers and they felt like small chards of something hard. As for the squeal, it sure sounded like the trans, but this was when I was buying it at SSVDP's house and was warned by him that there may be a problem with the trans. Maybe we are both wrong, it's happened before (so the wife says)!!

OK, so heres what I'm gonna do!! I'm gonna adjust the rear band according to the procedure given by fishy and button her back up with no sealer and fill it up with fluid. Then I'm gonna check the procedure for adjusting the 2-3 band and adjust that and take it for a ride. I'll check the belts first and make sure they're tight. I'll put a little pressure on the trans up the hill by my house to see howw she does and report back.

Thanks again for all the replies guys, it sure helps alot getting help on areas where you're not sure about things. That's why i love this site so much, so many good people willing to share!!!Geof
 
I would atleast put sealer on the pan side,that is the side that tends to leak.Remember these surfaces are 40 years old and the pan may have been on and off a few times.Better to be safe than sorry.

Jim
 
You're right Jim, and I have a few extra 904 gaskets from changing filters and such on the GTX so it can't hurt to brush some sealer on. My experience with that GTX trans has had me at the end of my trannie rope for a couple years now, and this week I'm sending it over to my trans guy to find that pesky leak once and for all!!! Thanks for the input!!! geof
 
part # for

727 is 2464324ac

904 is 4295875ac


use those gaskets from the dealer...they have a wire o-ring .....re-usable.....no sealer needed...no leaky....
 
I'll say this....never in my life have I had to put sealer on a trans pan gasket to stop a leak....and I don't recommend it.
 
I have never put sealant on my trans pan gaskets and not had any leak from the pan.
 
I'll throw my $.02 worth in too.....Hammer the pan rail flat around the bolt holes, clean it off real good, put a light coat of CopperCoat sealer between the pan and gasket and nothing between the gasket and case. This is what I do with a conventional cork or paper gasket. If it's the rubber/reusable ones, no sealer at all. Just about any ATF will work (except type A) but since they're all about the same price, use the latest and greatest Dexron or ATF+4 for their added properties. As fishy68 said, an auto trans squeal is virtually unheard of. If it makes that noise just sitting still, take off all the belts and fire it up for a few seconds. If it's quiet now, it's something driven by a belt. Spin those items by hand or start adding belts back on until you find the culprit.
 
OK gang, heres the latest on my project. After much reading of this thread and a call from a reputable trans friend, I am going with your recommendations regarding the gasket. A light coat of copperseal brush on between the pan and the gasket, just to keep it in place while I put it on. Next, I bought 2 gallons of Dextron fluid and am satisfied that it will be sufficient. The information from my trans friend and a 1971 service manual regarding band adjustment is this... Tighten the low/reverse band (the one inside the pan) to 72 in/lbs., then back off the adjustment 4 turns for 318 models, then torque the locknut 35 ft/lbs...the 2-3 shift band on the outside is also adjusted to 72 in/lbs then backed off 2 turnsand the locknut is torqued to 27 ft/lbs.

As for the squealing noise...the noise happened to me twice, once when I was putting it up on the trailer and the nose was up but the rear wheels were not yet on the ramp and I gave it some gas to get it up. The second time it happened I was taking it on it's maiden voyage around my block and hit the gas kinda hard to see if it would squeal again, which it did. Under light acceleration it does not do it, and I haven't had a chance to check it again. I checked the belts and they appear tight, and they are also new. The general consensus is that it is not the trans making this noise and that a trans would not make a noise such as this, so as soon as I get the trans buttoned back up I am going for another ride and a thorough check of this noise. I will report back as soon as the ride is taken. Thanks again for all your input everybody, it sure helps alot to be able to concur with so many people and come up with a plan that works!!! Geof
 
OK gang, update time...

I used some copperseal brush on gasket sealer on the pan side, and flattened out the pan as suggested by cudamark, got it all back together..no leaks and filled 'er up with fluid. Took it for a ride...no noise. However... and thats a big however...she's slipping like a teacher on a banana peel in forward. Reverse she takes right off but i'm-a-thinkin' that the trans is gonna need to come out. I didn't adjust the 2-3 band, and I'll try it to see but I ain't holding my breath!! Thanks again for all the replies, Geof
 
Geoff if it slips in low gear the front band adjustment won't do anything for it. It's for 2nd gear only. Has absolutely no affect on any other gear.

Did it have much metal/mud in the pan?
 
cosgig said:
OK gang, update time...

I used some copperseal brush on gasket sealer on the pan side, and flattened out the pan as suggested by cudamark, got it all back together..no leaks and filled 'er up with fluid. Took it for a ride...no noise. However... and thats a big however...she's slipping like a teacher on a banana peel in forward. Reverse she takes right off but i'm-a-thinkin' that the trans is gonna need to come out. I didn't adjust the 2-3 band, and I'll try it to see but I ain't holding my breath!! Thanks again for all the replies, Geof
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Double check the fluid level.....hot, idling in neutral on flat ground.
 
We were always taught no sealer on a transmission pan gasket. You don't want any excess getting in the transmission. Also, Type F has different friction modifiers in it. It will shift harsher and cause accelerated wear in the transmission. Use what it calls for, which is Dexron, or these days Dex II, III or the newer synthetic Dex VI.
 
fishy68 said:
Geoff if it slips in low gear the front band adjustment won't do anything for it. It's for 2nd gear only. Has absolutely no affect on any other gear.

Did it have much metal/mud in the pan?
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Well fishy, it slips in low gear, but not if you are backing up. It revs right over the trans until you let off and then will move about. I did go easy on it and it did shift through the gears but you can't just take off.I pretty much know that the outer band adjustment is for the 2-3 band and that's not going to have an effect on the problem, and that the trans will probably have to come out. As for the mud in the trans...yep, there was some!! Not what I would call a lot but definetly more than I wanted to see. There was a round magnet in the corner of the pan that was covered in mud, and when I tried to wipe it clean was very reluctant to come away from the magnet. It had magnetic properties and I think there was enough mud in the pan to conclude that the source is probably the band and that a rebuild is necessary. Unless the Mopar Gods (or you) can come up with some suggestion or miracle fix, I think this trans is toast!!

I let the trans warm up, took it through all the gears, went around the block, came back and checked the fluid level, right on the money!! I don't think it's a fluid level problem, but I'm gonna do the same thing again before I do any yanking out of the trans. I have another 66 trans, and I'm not sure this is a 66 trans in there as it has a replacement 1971 motor. Could this have any effect on the trans if it is a 66 trans hooked up to a 71 motor?? It is a floor shifted car and the bracketry looks to be original, but the motor is definetly replaced. Thanks guys for all the input!!! Geof
 
I dont use sealant on a trans pan gasket but I'll spend an hour working the pan back to as flat as the bottom of the trans. My growl comes from the new gasket being folded and crammed in a small box. All other gaskets are packaged flat. Who decided the trans pan gasket doesn't need to be flat ? Find him and slap hime for me. LOL
When the gasket doesn't have undersized holes that allow a bolt through to hold the gasket in place or anywhere those aren't sufficient, I'll tie a small piece of sewing thread though a bolt hole. Once the bolt is started I snip the thread and remove it.
White, pink, any light color thread is recommended. That matters since a piece of thread left there would just cause a leak.
 
That squealing you were hearing is called "Valve buzz"
It's the pressure regulator valve in the trans moving back and forth real fast.
The slipping AND the mud/flakes in the pan are from the direct input clutches being fried.
Gaskets that are folded up can be tacked to the pan with what you were told to hold it in place during installation.
Glad you have another trans you can put in.
 
cosgig said:
Well fishy, it slips in low gear, but not if you are backing up. It revs right over the trans until you let off and then will move about. I did go easy on it and it did shift through the gears but you can't just take off.I pretty much know that the outer band adjustment is for the 2-3 band and that's not going to have an effect on the problem, and that the trans will probably have to come out. As for the mud in the trans...yep, there was some!! Not what I would call a lot but definetly more than I wanted to see. There was a round magnet in the corner of the pan that was covered in mud, and when I tried to wipe it clean was very reluctant to come away from the magnet. It had magnetic properties and I think there was enough mud in the pan to conclude that the source is probably the band and that a rebuild is necessary. Unless the Mopar Gods (or you) can come up with some suggestion or miracle fix, I think this trans is toast!!

I let the trans warm up, took it through all the gears, went around the block, came back and checked the fluid level, right on the money!! I don't think it's a fluid level problem, but I'm gonna do the same thing again before I do any yanking out of the trans. I have another 66 trans, and I'm not sure this is a 66 trans in there as it has a replacement 1971 motor. Could this have any effect on the trans if it is a 66 trans hooked up to a 71 motor?? It is a floor shifted car and the bracketry looks to be original, but the motor is definetly replaced. Thanks guys for all the input!!! Geof
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How does it take off in manual low? If it's ok when you do that, it's a clutch pack that's worn out.
 
Mopar to ya said:
We were always taught no sealer on a transmission pan gasket. You don't want any excess getting in the transmission. Also, Type F has different friction modifiers in it. It will shift harsher and cause accelerated wear in the transmission. Use what it calls for, which is Dexron, or these days Dex II, III or the newer synthetic Dex VI.
Click to expand...
That's why I like CopperCoat. Just a thin layer won't squeeze out and clog something, plus it doesn't take all day to get the residue off. It's a rubber cement so once it gets tacky, it will hold a gasket in place easily.....even the bent ones.
 
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