Rear axle question.

[stump_puller]

Have a question about rear end temperatures. Went for a about a 30 mile drive and the rear end cover is hot. Can’t keep my hand on it. I sprayed some water on the cover it doesn’t sizzle but drys very quickly . Sorry don’t have a temp gun.
so my question is is that normal I haven’t ever Felt the rear end cover of any vehicle before so this is all new.
Truck has been down for a year and getting it back on the road again and want to drive it more instead of trailering it everywhere.

 

[Wes Harden]

I temp gunned my diff after a break in run with new gears, and it was 167°. On the trip to Moab this year I temped the rear diff, after it puked out some gear oil (over full I believe) it was in the 140° @180 miles at 70+ mph. Could I keep my hand on 140° diff cover maybe for a minute or so, but I also can handle the hot dinner plates the waiter warns everyone not to touch, your results may vary.

 

[tarussell]

Just as Wes said about being able to tolerate a hand on a hot diff cover varies - this sounds like a good reason to give your truck a diff fluid change and an opportunity to inspect the old oil condition for signs of excessive heat or contamination.

 

[stump_puller]

Gonna grab a heat gun tommorow. Should have one anyways as it is a useful tool for engine diagnostics. I’ll take the truck out tomorrow and run by harbor freight. Way better to know exactly then the “it’s hot to touch”
Thanks!
I’ll check back after but at least now I have some numbers to start with.

 

[Blue85]

I temp gunned my diff after a break in run with new gears, and it was 167°. On the trip to Moab this year I temped the rear diff, after it puked out some gear oil (over full I believe) it was in the 140° @180 miles at 70+ mph. Could I keep my hand on 140° diff cover maybe for a minute or so, but I also can handle the hot dinner plates the waiter warns everyone not to touch, your results may vary.

Come on, when Wes measures 140F, that's the ambient temp.

 

[tarussell]

The temp numbers really need to be compared in proper context:

What kind of rear end are we dealing with?

Is this a normal driving condition?

What gear ratio are we dealing with?

What speeds were reached and for how long?

What kind of loads are applied - towing, larger tires, etc. ?

For the most part 170* ~ 210* are normal for a heavy truck at lower speeds but once the temps start climbing over 220* then the oil change intervals need to be increased to avoid breaking down and loosing wear protection.

Let us know what ya find?

 

[stump_puller]

Got a temp gun and hit the road again today for another 30 mile drive. Drive consisted of rural roads so speeds were anywhere from 40-55 up and down hills. Temps reached 145-150 halfway thru the drive and when I finished. Looks like I’m good.
Thanks for the help guys feel a lot better on driving the down the road and Not having to trailer it a 100miles to the trails by the house.

Anyways for context here is the setup:
D60 rear axle, 5:13 gears with a lunchbox locker. 37” super swamper sx2 on beadlocks. I’d say normal driving as I’m still breaking in fresh rebuild on my trans (reason I had to trailer the truck). Speeds were 40-55 up and down hilly rural roads. Temperature out side was at 70 give or take a couple degrees.
Again thanks for everyones help!