Anyone have tips for making gaskets leak proof

[chance9888]

Hi all. I feel like i'm the only person who has been posting questions on this forum since I began. Please excuse me, i'm still fifteen (90's child!). Anyways, the transmission, PTO, and rear differential on my truck have all been rebuilt. The problem I see with them is that everywhere I have a gasket/seal, there is a slow drip of oil. Not much, but enough to get on my nerves. I have changed quite a few of the gaskets. In most cases, I replaced what was there with 3x of gaskets from VPW. Is there some sort of glue or something that i can apply or are there any good tricks to prevent these leaks from occurring? I feel that at the time of the trucks manufacture, oil leaks weren't big deals...

[chance9888]

Would some sort of stop leak product work well with this? I'm just a little snowed under because they are not engine oil leaks. We're talking SAE 80-90 oil, here.

[Desoto61]

Are you using an RTV or anerobic type sealant with the gasket? A light coating or bead on each side of the gasket sealing surface should help resolve most leaks.

You also might want to check and verify it is actually the gasket. A seal over a worn shaft will allow for leakage, a redi-sleve should help with that. Oil can also leak around the drive shaft splines and out the large nut on the end of the yokes. Some RTV on the washer can help stop that.

[chance9888]

Sorry, i didn't make myself very clear. The leaks occur not so much on things like the seals but between different parts of the transmission where I anaerobic gaskets.

[Desoto61]

Anerobic gasket maker is similar to RTV except it only hardens in the absence of air (anerobic). One of the advantages is you are less likely to have globs of the stuff that can harden and come loose in the component if you over apply it, however if you don't have a good joint it won't harden proprly since it's still exposed to air.

You can usually find it next to the RTV sealers at your local auto parts store. A thin coat of RTV on both side of your gasket will probably be your best bet. Follow the directions and make sure both surfaces are clean of any oil residue by wiping with alcohol or some brake cleaner on a rag first.

[Chris Olson]

Permatex

For those really stubborn surfaces that just don't seem to want to seal...
First... are they flat? sometimes just scraping the gasket surface down to bare metal and then going over the surface lightly with a single cut file will give a visual reference for any burrs or imperfections that are not allowing the gasket to do it's job
Second, apply Permatex Aviation form a gasket #2 to both surfaces along with a new gasket..
Third, Are any of the fasteners exposed to oil from the back (as in a through tapped hole in a transmission, engine etc.) if so you will have to clean out the threads and use thread sealer on those bolts to keep the oil from seeping along the threads