Posted by MoparNorm on Monday, October 04, 2004 at 2:06PM :
In Reply to: How hot is HOT (Rear differential) posted by Dave in Plano, TX on Sunday, October 03, 2004 at 2:38PM :
Vaughn is correct (that's redundant isn't it? ha!ha!).
Since you didn't indicate how hot, touching isn't really a scientific measurment and it is uncertain how hot the oil/grease actually was. Constant running gear/transmission temps of 200+/- degrees are normal, with failure of lubrication starting to occure at around 240 to 260 degrees. If you have a way to accurately measure the lubrication temperature, while under load, then I'd be concerned at temps over 220 degrees, which by the way will burn your hand. The temps that you can feel with your hand are most likely under 120 degrees* and the gears should be fine, unless you are hearing bearing failure noises.
MN
*PS:I could NOT touch the remaining tire on Ed's damaged trailer while driving back from Texas, THAT, was hot for rubber and sidewall damage most likely resulted. Instant skin burns and boiling blood begins at 125 to 140 degress, keep that in mind when adjusting your hot water heater. 120 degrees feels like 140 to the human hand, but damage results at 140 degrees and under 120 degrees is generally considered safe for most people.