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RTV th350 pan gasket

76k5blazerr

76k5blazerr

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I need to replace the pan gasket on the th350 in my 72 c10. It is leaking. I am wondering if the pros and cons of doing a straight up "gasket maker" gasket. As in running a good bead of gasket maker around the pan and bolting it up. No cork/rubber. I am thinking doing it this way it will not leak. What do y'all think?
 
The con is that when you have to drop the pan next time, you get to scrape the entire rail clean.

Don't they make any sort of higher end seal like the fel-pro silicone ones made for engine oil pans?

I was always a fan of the rubber gaskets over cork, simply because back when I ran automatics, I was always having to drain the fluid to pull them. I could reuse the rubber one.

Probably would have failed eventually, but I didn't run it long enough to harden up I guess.

Personally my favored approach IF I used a gasket and sealer, was to seal the pan side, and leave the housing side bare. Scraping junk off valve covers, trans pans, or diff covers is a lot easier than trying to get it off whatever component is still in the vehicle.

Besides, unless it's visibly screwed up, the trans pan mating surface is guaranteed to be flat...the pans are what don't seal because the rails get warped.
 
dyeager535 said:
The con is that when you have to drop the pan next time, you get to scrape the entire rail clean.

Don't they make any sort of higher end seal like the fel-pro silicone ones made for engine oil pans?

I was always a fan of the rubber gaskets over cork, simply because back when I ran automatics, I was always having to drain the fluid to pull them. I could reuse the rubber one.

Probably would have failed eventually, but I didn't run it long enough to harden up I guess.

Personally my favored approach IF I used a gasket and sealer, was to seal the pan side, and leave the housing side bare. Scraping junk off valve covers, trans pans, or diff covers is a lot easier than trying to get it off whatever component is still in the vehicle.

Besides, unless it's visibly screwed up, the trans pan mating surface is guaranteed to be flat...the pans are what don't seal because the rails get warped.
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I may look for a higher quality gasket, I just don't want to have to do this job twice in a week because it leaks lol. Are you saying to run a bead of rtv on the pan, then lay down a gasket then bolt it up?
 
The sheet metal rail on the pan tends to be squashed over time from people monkey-pawing it. When you replace it, put a socket under the bolt holes and use a ballpein hammer to reverse dimple it slightly.
 
One piece felpro, reusable, only way to go. Pricey but worth it. All that RTV not needed.
 
and make sure the seal surfaces are DRY no atf fluid or it will make a path for the next spot to leak .
 
Permatex now has a ATF specific RTV sealant just for transmission pans..personally I avoid using RTV on an automatic,for fear some might get inside and gum up a solenoid or passage,but some manufacturers use RTV alone with no gasket (Chrysler for one)...
I would use it sparingly and only on the pan side with a gasket like Dygear suggested...
Wix filter kits come with a rubber type gasket that seals a slightly warped up pan better than a cheap cork gasket..they install easier too,due to having some of the bolt holes cut in it a bit undersized,so it'll hold the bolts and gasket in place..
 
76k5blazerr said:
Are you saying to run a bead of rtv on the pan, then lay down a gasket then bolt it up?
Click to expand...

Yes. But as mentioned, another downside to RTV is that if you go crazy with it, you may end up with it clogging stuff up internally. It's unlikely, that's why there is a filter, but I've taken things apart others have RTV'd and you just shake your head.

The bent pan rails (particularly around the bolts) are very common, and normally the reason they don't seal well. If factory reinforced with the dimpled ridges, it makes it very hard to try and straighten them yourself to any degree of certainty.

If the Fel-Pro gasket is available, just use it.
 
I think I'm just going to buy a new pan from summit. They are pretty cheap. Then also gonna get a 1/4 inch thick gasket I found that is supposed to be good. Planning to install a temp gauge in the new pan as well.
 
watch out for chrome ones . seen lots of them never stop leaking .

had to swap on a old steel pan for a friend after we tried every thing . old rusty steel sealed first time.
 
Stay away from the Chrome pans and the polished cheapo aluminum pans, they leak from the rail as well as the drain plug. There are cast pans in the $100 range that offer excellent sealing with almost any pan gasket. An original steel pan can be made to work well provided the surface is straight and flat and the holes are not pooched up. Use a good quality Duraprene or Farpack pan gasket with a light spray of gasket sealant to either side and you should be golden.
 
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