On my 2004 FG649, I noticed the other day after driving on the highway for 30 minutes or so that my rear differential was pretty hot. I was able to place my hand on the diff cover and keep it there for maybe 2 or 3 seconds before I had to pull it away. Not the most precise of measures I realize, but nonetheless, does this sound normal-ish? I did just recently drain and fill both diffs, so the oil level is good.
How hot should the rear differential get?
- Thread starter glennm01
- Start date
nickw
Adventurer
Pretty normal(ish) I think....it wouldn't worry me unless it was unbelievably hot to the touch. There is a lot going on there, heat transfer from brakes, seals, bearings, gears, oil....
Aussie Iron
Explorer
As long as you put the right oil in, it sounds fairly normal. Don't forget they are Limited Slip so every corner the clutch packs are slipping creating heat.
Dan.
Dan.
jadmt
ignore button user
I have been driving since the 70's and I have found that differentials never get very hot. I do not ever recall having one that was hot enough I could only touch it for 2 seconds, but I have never had a fg649 so that might be normal for those. get an IR temp gun and see how hot it is.
nickw
Adventurer
Here is a good thread over on Pirate4x4:
www.pirate4x4.com
And a quick search for heavy big rigs:
www.thetruckersreport.com
Seems like those big rigs are running high 1XX's to low 2XX's, your's is probably quite a bit cooler than that, but your obviously not putting the stress on your rear end(s) like they are.
how hot should your rear diff get?
www.pirate4x4.com
And a quick search for heavy big rigs:
What Temp should the drive axles be at?
What Temp should the drive axles be at? My front Axle keeps riding at about 220, and the rear is around 160. Just to throw it in there tranny is about...
www.thetruckersreport.com
Seems like those big rigs are running high 1XX's to low 2XX's, your's is probably quite a bit cooler than that, but your obviously not putting the stress on your rear end(s) like they are.
I got my hands on an on IR temp gun, and after a good solid 90 minutes on the freeway, I was surprised to see that it was only showing 130 degrees Fahrenheit. Interesting to see the difference between what *feels* hot and then the actual temp. I would've guessed a much higher temp would be required to render something untouchable for more than a few seconds, but after researching the matter, it seems that around 120 is considered the safe upper design limit for anything that needs to be touched by human hands. The things you learn... Anyway, I guess this was all much ado about nothing. Thanks to all for the insights.
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