Has anyone used this product for the diff covers on these trucks?

Is there anything better to use?

 

The factory puts 'em together with RTV. The cover doesn't fit tightly enough to use the Loctite Gasket Eliminator 510 product (if that's what you mean). The 510 is intended for tightly fitted joint, casting to casting kind of application. Plain ol' blue goo is better for a sheetmetal to casting seal (like a diff cover or trans pan).

 

DC has a tube of grey RTV labeled something like "Axle Cover Sealant" - I tried it out some time ago when I stopped in to get the limited slip additive. It worked fine. Last time I changed the gear oil I just used good old Permatex Black RTV because it was on the shelf in the shop, the same thing I have been using for many years. Can't tell the difference in performance. YMMV.

RTV does not do real well if it is a thick layer and under pressure. Rear ends do not get that hot and should not have any pressure buildup so it works fine.

 

Great, this is exactly what I wanted to find out.