Hi all,

Well, I am glad I called Permatex because I almost used the Ultra Black RTV for a differential cover attachment.

1) Permatex recommends ONLY the 81182 Gear Oil RTV if friction modifiers are involved. Apparently the friction modifiers make the oil highly acidic and this can "go right through" their other products.

2) Permatex does NOT recommend letting the RTV skin before mating the surfaces. They want the surfaces mated while the RTV is wet to maximize adhesion. To start, only finger tight on the bolts. Wait one hour for the RTV to cure some and then torque to spec. Then wait 3-4 more hours before filling with oil.

I wanted to put this out there because there are a number of posts that recommend a different procedure.

Don't like how this reads? Take it up with Permatex!

thanks,
Dave

 

Well I put RTV on mine and no leaks so far. The key is that both surfaces are dry to start with. Silicone is pretty tough stuff. It came with Silicone on it.

Perry

 

I have had the best luck using the gray for oil and gear oil applications. Been using it for about 10 years now without issues. I rarely use black, blue, orange, etc. The most important thing is getting everything clean clean clean. I use acetone to wipe down all mating surfaces before applying sealers. Also excessive rvt is bad. Excessive "squish" will let chunks of the rvt to break off inside the motor/rear end/tranny/etc. and can cause very bad things to happen. More than a few times now I have seen oil pick up screens completely blocked off from RVT chunks.

 

Good point if that is the case.

I'm not taking any chances as this is a job I don't want to repeat !!

 

i just use permatex gasket maker on mine, works good, always have used orange or black rtv or the blue, never had a problem



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Permatex 80628 Features:

• General purpose gasket maker creates reliable "formed-in-place" gaskets
• Easily makes cut gaskets in various shapes and sizes while eliminating costly inventory of cut gaskets
• Formed gaskets will resist shrinking, cracking, and migrating
• Low volatility
• Cures to a strong, flexible rubber which seals flanges against leaks and resists oil and other shop fluids
• Increase reliability of pre-cut gaskets by coating with Sensor-Safe
• Intermittent temperature range of -65°F to 500°F (-54°C to 260°C)
• Fully cured, fills gaps to .25"