Rear differential temperature

I’ve always changed diff and trans at 250,000 miles on synthetic.

 

Have never had temps in that range. Even heavy in texas heat. First thing I would try is changing lubricant. Synthetic or not, over time with heat and cool cycles on top of running tends to use up what little additive package is in the lubricant. One of the things that can take a toll is most differentials are vented to atmosphere, so they will be susceptible to condensation. Running down the road will heat them up and potentially boil off the water, but the acids that form plus the dirt stays behind.

 

Eaton tells you that 150 + outside temp is normal on a long pull.

 

More than you ever wanted to know about gear oil testing(possible bias)
http://www.lastgreatroadtrip.com/wp-content/uploads/2010/11/gear-oil-comparison.pdf

A good discussion on both gear and engine oil viscosity and causes of breakdown.
Gear Lube Temperature - Automotive lubricant engineering - Eng-Tips

 

My trans and rears will creep to the other side of 250 when pulling a pass, then will usually creep up a little more jaking down the other side. I run 100-105k in the Northwest.

 

Just had a truck come into the shop with the same issue. Had a short in the wires going to the temp sensor sending a false temp reading. See this post is from 3 years ago but figured I'd add that for any others that might need it.

 

Thanks for doing that. A lot of the older threads contain good information.

 

Buy a flir temp gun and check the diff housing. Temp sensors are not all that accurate. I carry a temp gun snd walk around and shoot my hubs every time I stop. Front diff will usually always run hotter due to power divider and more friction in diff housing