Transmission gaskets.

[carguy300]

Can anyone tell me a good maker or a good place to get transmission filter and gasket for my 68 300? I need to go ahead and change these out while ive got the car up on jack stands. Another new project for me. Doesnt look to be to difficult. Any quick tips?

 

[CBODY67]

Use an electric extractor pump (think zero-turn lawn mower oil change; used to be about $30USD at Home Depot) to get the fluid out first. Not so much of a mess that way.

CBODY67

 

[MoPar~Man]

When I dropped my 727 pan earlier this year to have it powder-coated (both sides) I looked through rock auto's offerings for gaskets, I wasn't interested in any cork or cork-composite gaskets, the only one that seemed 100% synthetic was ATP GT10 (about $5). That's what I got. I spread some silicone dielectric grease on it when I installed it, I also changed the shift-lever seal. Nothing has leaked. I had to tweak the connections for the new lines I bent and installed, but nothing leaks now, that's just what I wanted.

Rockauto's photo of the gasked shows a highly rugged surface, like heavy orange peel, but that's not what this gasket looked like. It was totally smooth.

I also bought a new trans filter, it probably came with a cork gasket (or 2 gaskets, for 904 and 727) but it was cheap and I just used the filter.

If you buy the ATP TF30 kit (like $7) it comes with the filter and probably the same gasket I used (ATP GT10).

Right now there's an AUTO EXTRA 61658707 filter/gasket kit on wholesaler discount for like $1.50, gasket also looks like non-cork.

You might want to also change the output shaft seal while you're at it, since you're going to be draining the fluid.

I don't know if you're going to save the fluid or not, but if you're putting in new stuff there's cheap and there's expensive. The expensive is ATF+4 and it will last longer - more shear and heat-stable than the cheap stuff (either mercon or dexcon, I forget which one).

 

[carguy300]

Use an electric extractor pump (think zero-turn lawn mower oil change; used to be about $30USD at Home Depot) to get the fluid out first. Not so much of a mess that way.

CBODY67

That makes sense! Better than a face full of fluid!

 

[carguy300]

When I dropped my 727 pan earlier this year to have it powder-coated (both sides) I looked through rock auto's offerings for gaskets, I wasn't interested in any cork or cork-composite gaskets, the only one that seemed 100% synthetic was ATP GT10 (about $5). That's what I got. I spread some silicone dielectric grease on it when I installed it, I also changed the shift-lever seal. Nothing has leaked. I had to tweak the connections for the new lines I bent and installed, but nothing leaks now, that's just what I wanted.

Rockauto's photo of the gasked shows a highly rugged surface, like heavy orange peel, but that's not what this gasket looked like. It was totally smooth.

I also bought a new trans filter, it probably came with a cork gasket (or 2 gaskets, for 904 and 727) but it was cheap and I just used the filter.

If you buy the ATP TF30 kit (like $7) it comes with the filter and probably the same gasket I used (ATP GT10).

Right now there's an AUTO EXTRA 61658707 filter/gasket kit on wholesaler discount for like $1.50, gasket also looks like non-cork.

I want to change both. Did the powder coating come out good. I just had my air breather done gloss black.

 

[MoPar~Man]

I'm totally satisfied with the powder coating job, I had a bunch of stuff done including the entire stub frame, lower and upper control arms, brake backing plates and knuckles, front strut rods. All of that was done in a medium gloss black including the trans pan. I had the engine oil pan done in what I think was the best-matching Chrysler engine red.

 

[carguy300]

Sounds like a whole lot more than I did to mine! Im sure it looks awsome!

 

[65CopCar]

In my opinion the only gasket to use is the Mopar o ring gasket. Hands down can't be beat.

 

[MoPar~Man]

In my opinion the only gasket to use is the Mopar o ring gasket. Hands down can't be beat.

I believe this is also known as the reusable gasket, mopar P/N 2464324AC.

Rock auto does sell this, but you have to look for it by PN, it doesn't show up in the parts listings transmission / gasket section. Their price is $40.

(this gasket does, or should, come with longer pan bolts?)

 

[CBODY67]

Once into the catalogs at RockAuto, IF that pan gasket fits your application, it is listed under the "Mopar" brand. It is also about the price mentioned, BUT it is also rated as "Reuseable". Which also means that each bolt hole has a bushing in it to result in a consistent crush amount of the gasket as it is tightened.

Getting a transmission oil pan powdercoated black inside might not be advisable. Reason? With the normal silver/steel color, when the pan is removed for future filter changes, it is easy to see what is in the pan, as to clutch material and "metal", without having to strain the oil through a white coffee filter as it is poured into a container for disposal. Just something to consider . . .

Enjoy!
CBODY67

 

[carguy300]

I was thinking that the inside of oil pans would not need to be painted.

 

[3175375]

I believe this is also known as the reusable gasket, mopar P/N 2464324AC.

Rock auto does sell this, but you have to look for it by PN, it doesn't show up in the parts listings transmission / gasket section. Their price is $40.

(this gasket does, or should, come with longer pan bolts?)

Amazon sells this one too:

https://a.co/d/coFlzvK

 

[MoPar~Man]

Amazon sells this one too:

https://a.co/d/coFlzvK

It looks to have a metal core, gasket made of neoprene rubber? One video review shows it splitting apart in several places after it had been installed. Price is high - $45 maybe more.

 

[3175375]

It looks to have a metal core, gasket made of neoprene rubber? One video review shows it splitting apart in several places after it had been installed. Price is high - $45 maybe more.

I have one on Elwood my 68 Fury II 4 door sedan with a 904. Well made and sound, in my opinion.

 

[MoPar~Man]

I was thinking that the inside of oil pans would not need to be painted.

My engine oil pan was not powder coated on the inside (I didn't want it to be) but I was ok with doing it with the transmission pan. Anyone doing powder coating will want to apply it around (wrap around) sharp edges because the coating will hold up better over time vs coating up to the edge and stopping. The coating is cured at 400 f degrees so I figure trans heat won't damage it, I'm not sure about the oil long term. I think maybe the pan will seal better if the gasket surface is powder coated?

 

[mgm1986]

My experience with my '68 300 has not been great when it comes to the transmission pan gasket.

I have had the pan off several times to try and stop the leaks from the gasket. Cork, Mopar rubber, cork with a light coating of silicone, Mopar rubber gasket with silicone. Every time it has leaked. Frustrating.

Now I am waiting for a new trans pan with a drain plug. This way if it leaks, I can at least salvage some of the fluid as it gets expensive dumping $60-$80 of trans fluid every time you drop the pan.

Good luck, I am hoping you have better luck than me stopping your leak!

 

[65CopCar]

My experience with my '68 300 has not been great when it comes to the transmission pan gasket.

I have had the pan off several times to try and stop the leaks from the gasket. Cork, Mopar rubber, cork with a light coating of silicone, Mopar rubber gasket with silicone. Every time it has leaked. Frustrating.

Now I am waiting for a new trans pan with a drain plug. This way if it leaks, I can at least salvage some of the fluid as it gets expensive dumping $60-$80 of trans fluid every time you drop the pan.

Good luck, I am hoping you have better luck than me stopping your leak!

Lots of times when you get in a situation like that its not the gasket. There is a rod in the back just above the rail that can leak and make it look just like a gasket leak. Been there, done that.

 

[mgm1986]

Lots of times when you get in a situation like that its not the gasket. There is a rod in the back just above the rail that can leak and make it look just like a gasket leak. Been there, done that.

Yes, great point. On the second attempt to repair the leak I added UV dye and fixed the leaks from the speedometer cable, under the trans mount and around the dip stick. If you have a picture to elaborate on this rod that would be awesome.

That said, I don't want to hijack this thread just wanted to share my experience in an effort to help @carguy300 get his fixed right the first time.

 

[65CopCar]

Yes, great point. On the second attempt to repair the leak I added UV dye and fixed the leaks from the speedometer cable, under the trans mount and around the dip stick. If you have a picture to elaborate on this rod that would be awesome.

That said, I don't want to hijack this thread just wanted to share my experience in an effort to help @carguy300 get his fixed right the first time.

Here ya go.........

 

[65CopCar]

A temporary fix is clean good and slop with RTV..........