Rear Diff tempature

[JAllen]

What is normal for the rear diff temperature?



At what temperature should I start being concerned?



With the truck empty and not towing anything the temperature runs around 100 to maybe 125. Depends on outside temperature and driving speed.



This weekend I was towing about 4000 pounds at 70 to 75 mph and the temperature got to a little over 200. The outside temperature was between 85 and 90 during the driving.



The trans temperature would get up to a little over 180 when I first pulled out on the road, stop and go to get to the expressway. Then is would settle down to about 165 and the rear diff temperature would start rising.

 

[BillGotthelf]

Hmmm sounds a little high towing. You may want to try running synthetic in the rear. I saw 175-180 towing 13000lbs at 70. I saw 200 only once towing on a hot day in the Blue Ridge Mountains.

 

[Turbo Thom]

The only time I see 100 is on the way up to 150. Empty I stay around 150-160. Towing 15K lbs I around 180-190. On a hot day I have seen 220. I slowed down to 65 and the temp came down to 190. I run the 140 W synthetic and it still gets hot. I was told not to worry about 220 that the big trucks go to 260. I really don't know but that is the temps I run. The 140 is supposed to be better for towing but I get less heat from the 75W-90.



Preston. .



. . Preston. .