A few days ago, I noticed a two-inch spot on the left side of my rear differential cover that has the paint flaking off. I thought that it could be the result of a hot spot. They replaced my rear locker this summer after Camp Jeep, and maybe they didn't get the pre-load set on the bearing. So I drove about thirty minutes today and checked the temperature of the differential with a laser pyrometer. The flaking part on the left is within 1-2 degrees of the right side, and the center is about 20 degrees warmer. The left and right sides were about 120 deg F, and most of the center was 135-140. There were no spikes, and it felt warm to the touch, but not uncomfortably so.

There are no leaks, and the gasket material they used is present around the edge of the seal.

Should I be worried about these temps? It could be that they dropped the diff cover when they removed it, and the paint is peeling as a result. I'm not concerned about the cover itself, as it will be replaced with a heavy duty Solid, Ox, or Arb when I change the gear oil at 30K, (about 8K or 3 months from now.) But if I have a problem with my gear or axle, I want to let them know while it is still under warranty, and before the paint peels on my new diff cover.

Any ideas?

 

It seems to be the general consensus that the stock differential covers have lousy paint. How much does those laser pyrometers cost?

 

I know you can get a cheap relatively accurate one at harbor freight for around $30. It should be accurate to within a few degrees, at worst. I used one of my work pyrometers that are considerably more expensive and accurate, with the calibration recertified yearly.

 

Yup. Mine did the very same thing after just 2 weeks.