Should the Inside Surfaces of a Diff Cover be Spray Painted or not?

[DC]

Alright, this is no doubt in the dumba$$ question category ... but here goes. I have rattle-canned just about everything over the years, but what about an unpainted aftermarket differential cover?

I have a modified Blue Torch Fabworks D44 Kyptonite diff cover that is currently unpainted steel. Now I'm not worried about the paint on the outside of the cover (I am inclined to use black Hammerite), however, what about the inside of the cover? Should the inside even be painted? I ask, as I don't want to spray paint it, only to find that the gear oil starts dissolving or otherwise attacking the paint over time (even when properly cured). On the other hand, I assume that I could get by without painting the inside, as it probably won't rust since it will have gear oil either directly on it or slung up on it. If anyone feels that the inside surfaces should be painted, can you make some recommendations as to the right kind of spray paint to use for this application?

Thanks,
Don

[DsrtJeeper]

OK....i'll bite. Why would you need a rust prohibitor on an oiled surface? The stock covers aren't painted internally and either is your engine.

[Stu Olson]

no interior paint necessary

[DC]

OK ... as I thought, I'll dispense with the interior paint. But how about a nice shiny chrome plated finish?

[mrblaine]

Originally posted by DC
OK ... as I thought, I'll dispense with the interior paint. But how about a nice shiny chrome plated finish?

Bought an axle once that had a chrome cover, care to guess how many coats of semi-flat it takes to kill the shine?

[NAILER341]

Originally posted by mrblaine
Bought an axle once that had a chrome cover, care to guess how many coats of semi-flat it takes to kill the shine?

one heavy coat will do it with the right paint

[mrblaine]

Originally posted by NAILER341
one heavy coat will do it with the right paint

I didn't shake it enough the first two times.

[DC]

Originally posted by mrblaine
Bought an axle once that had a chrome cover, care to guess how many coats of semi-flat it takes to kill the shine?

Let's see ... how about 6?

By the way, you might appreciate this Blaine. The real reason I started this thread was that "my" shop spray painted both the outside and inside of the new BTF D30 & D44 Kryptonite diff covers (which I subsequently dissolved off the D44 cover with MEK before returning it to BTF to modify for the rear Full Traction diff bracket). It got me thinking (potentially a dangerous opportunity), that if a bona fide 4x4 shop was to paint the insides of such an item, perhaps there was some secret validity to the act. Of course, this line of thinking might be akin to saying that "I read it somewhere, so it must be true".

[mrblaine]

Originally posted by DC


It got me thinking (potentially a dangerous opportunity), that if a bona fide 4x4 shop was to paint the insides of such an item, perhaps there was some secret validity to the act. Of course, this line of thinking might be akin to saying that "I read it somewhere, so it must be true".

Shops have rats, typically Hose A and Hose B, neither of which are able to actually discern the difference between the air and oil side of a diff cover.

[DC]

Originally posted by mrblaine
Shops have rats, typically Hose A and Hose B, neither of which are able to actually discern the difference between the air and oil side of a diff cover.

Well now, wait a minute! Do you mean to tell me that my shop should have mounted the diff covers with the curved side out instead of in??