I'm in process of redoing the IRS and Diff. I have new gasket for pumpkin. Also going to do transmission pan and Valve Cover Gaskets. Would like advice on use of Hylomar Blue (which I have) or RTV on various mating surfaces. Any do's and don'ts?

 

I've used the Hylomar Blue and stopped using it for some reason. It has a very good reputation, but I don't remember why I stopped. I now use "old fashion" Permatex #2 for nearly everything, except I am using Permatex gear lube RTV on diff.

Dave

 

Hylomar is for use with gasoline.

 

For diff covers I usually use Loctite 515 or 518 flange sealer.

 

The use of any gasket dressing is mostly dependent on the type of gasket. For example I like Permatex silicones with cork and I like to use Indian head shellac with papers and gascasinch with rubber or neoprene.

Hylomar blue is more for assemblies that need to be opened or checked often. It's not setting and will allow for disassembly with out tearing the gasket.
For some projects being able to reuse the gasket is a benefit especially when doing assemblies and re-checks on high performance items with expensive gaskets. I had a Lingenfelter intake that was like this. I had to often partially remove the top to check the tightness of internal bolts and the gaskets were expensive and seldom instock,

For the diff you most like will be using a paper gasket so Indian Gasket shellac is your best bet since I dont think you'll be in there often and for a diff you want a thick hardening type that can be painted on cleanly and completely.

 

Everyone has their favorites. I've tried so many but keep coming back to Permatex #2 for most tasks.

Cheers
DD

 

Permatex now makes one for "gear oil" and one for "transmission fluid". Both work very well.