What sealant do you use on the TH400 with pan gasket?
 

I am getting ready to reinstall the trransmission pan on my TH400 in my 1968 Chevy C10 shortbed fleetside.

I have a stock TH400 pan gasket with a cork gasket. Do you guys use some type of sealant with the gasket or do you just use the gasket and nothing else?

The last time I installed it a few months ago it leaked with this same trans pan and some type of composite rubber/cork gasket and a sealant that I used which seemed to take a long time to cure.

I appreciate any input.

Re: What sealant do you use on the TH400 with pan gasket?
 

I use an FIPG on all gaskets. It’s more expensive than other sealants, but it works like it’s supposed to and is used in OEM applications by Honda, Toyota, etc.

Re: What sealant do you use on the TH400 with pan gasket?
 

I've used CAT blue anaerobic sealant along with a gasket with good results in the past. I generally use anaerobic sealants on gaskets. Although last summer I used the Felpro sealant below on my T350 with a gasket. No leaks so far.

https://www.summitracing.com/parts/p...SABEgI1IPD_BwE

Re: What sealant do you use on the TH400 with pan gasket?
 

Double post.

Re: What sealant do you use on the TH400 with pan gasket?
 

I am going to use Permatex Ultra Black with that cork gasket. I hope it seals Wish me luck!

Re: What sealant do you use on the TH400 with pan gasket?
 

I use interior spray trim adhesive on the pan. Wait about 5 minutes, then put on the gasket. Flip it over on a flat surface and put some pressure on the pa for a few minutes. Install form there.

I have never had a leak.

Re: What sealant do you use on the TH400 with pan gasket?
 

Moroso silicon gasket no sealant last year so far no leaks

Re: What sealant do you use on the TH400 with pan gasket?
 

Only thing I use is gaska-cinch on the pan itself to hold the gasket in place. Other than that.....nothing. Use a quality cork gasket, make sure the pan is flat and the area around the bolts is not coned out and torque the bolts to 100 INCH pounds

Re: What sealant do you use on the TH400 with pan gasket?
 

Well I got it installed and the Permatex Ultra black sealant says to tighten up the bolts snugly. Wait 1 hour then tighten to spec. Then wait 24hrs to cure.

I am just going to snug down the bolts lightly with 1/4 ratchet using light pressure after 1 hr and then wait until tomorrow to fill the trans with fluid.

I dont trust using my torque wrench for the 12ft lbs as it seemed to squeeze out the gasket and sealant too much the last time I did that.

I will just snug the bolts again and then wait for it to cure as I have had better luck in the past doing that.

Re: What sealant do you use on the TH400 with pan gasket?
 

Straight cork gasket, no sealant.

Those are pretty much the instructions for not using a gasket at all. Like sealing a differential cover or T-case. On something like a AT pan gasket that shouldn't need a sealant to seal. There really shouldn't be enough sealant on there to squeeze out. It just makes the gasket slick. That's why it won't stay in place.

Re: What sealant do you use on the TH400 with pan gasket?
 

We will see. It will either leak like a faucet like you say or not.

Re: What sealant do you use on the TH400 with pan gasket?
 

I may have missed it, but what kind of pan are you using? If it’s the stock pan it may have been distorted by a PO due to over tightening. Valve covers and steel trans pans only require minimal torque to seal, it a lot easier f people will crank the bolts down tight and bend the metal. It doesn’t take much. If it’s a chrome pan, those are difficult to get to seal up.

Re: What sealant do you use on the TH400 with pan gasket?
 

Permatex the right stuff has never failed me, I prefer molded silicone gaskets with a steel core where possible over cork or regular rubber.

Re: What sealant do you use on the TH400 with pan gasket?
 

I never said it will leak like a faucet . . .

Re: What sealant do you use on the TH400 with pan gasket?
 

When I was putting my 71 back together with the turbo 400 I stopped at a long time friend's transmission shop to pick up a speedometer drive and then bought one of the cork gaskets as if it is good enough for him it is good enough for me.

Re: What sealant do you use on the TH400 with pan gasket?
 

Sorry! I got your post confused with another on a different site. Hopefully it seals!

Re: What sealant do you use on the TH400 with pan gasket?
 

FWW, I skipped the cork - and common rubber (junk) favoring a Moroso gasket #93103, with ARP bolts #651-0750 for my 400Th pan. No sealant and no leaks.

Re: What sealant do you use on the TH400 with pan gasket?
 

It sealed with no problems.

Re: What sealant do you use on the TH400 with pan gasket?
 

i used a lube locker gasket with nothing on it and its sealed up nice. i do have a deep aluminum pan however with a machined surface.