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Painting the Inside of the Differential Cover?

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KVH

KVH

Obi Wan
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I was all set to put my new gasket in, then noticed that the inside of the differential cover that I just cleaned was actually peeling. It was painted with a black paint.

I assume that paint is necessary to avoid internal rust??

I'd REALLY appreciate some advice on what procedure to follow to repaint the inside face of that cover. I can't put it back on knowing the paint is chipping off so badly.

Thx.
 
Just curious, but why would you want to paint something that is always covered with lubricant? The chances of it flaking and contaminating the lube or oil outweigh any possible benefit derived from the coating. It will never rust.

Of course, I realize how foolish my question must sound when thinking about why we would paint any engine parts on these cars, because, eventually, they will also be covered with oil.

I'd get rid of any flaked paint, buff it with a wire brush and reinstall the cover. You'll go to sleep happy knowing it's clean and well lubed once those gears start turning.
 
I'd think the lubrication would be enough to make rust a non-issue, but what concerns me is that it was painted to begin with. I think the level in the diff is normally so low, that there must be a belief that rust develops on the upper half if the car sits for extended periods of time. But I just don't know.
 
Kentvillehound said:
I was all set to put my new gasket in, then noticed that the inside of the differential cover that I just cleaned was actually peeling. It was painted with a black paint.

I assume that paint is necessary to avoid internal rust??
Click to expand...

There should not be paint in the differential any more than there should be paint inside of your engine. Just clean out whatever is peeling off. The second you drive, oil will be flung everywhere inside of the diff. I oppened up a diff which had been sitting outside, upside down for about 20 years, and there was not a spot of rust inside.
 
Yes, strip the paint off and forget about it.
 
Just to add to NickMorgan and 70Herald....there should be no paint inside the diff.

Why yours was painted to begin with I'm not sure. I have opened a few of them and have not seen one painted yet. Gear oil will cover the inside of the differential in operation, there is no need for anything else. Paint inside would suggest the diff has been opened by a PO.

I would not worry too much about the current paint flaking, though. I would clean clean it as best I can, but a few flakes that get into the gear oil are not going to contaminate it very much. The paint will just emulisfy into the gear oil. And they are not coarse enough to wear or damage the gears.

Make sure you use GL-4, not GL-5 in the diff.
 
There's no need for paint inside and you could safely strip it off if you're concerned about it coming off. Some engine builders use Red Glyptol on the their engine blocks and heads supposing it helps promote oil flow, but the benefit of that is minimal, if at all. Differential oil is so thick that all the metal surfaces should hold a film of it for considerable times after being used.
 
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