Dodge Dakota, 2006, v6. I drove for over an hour at highway speeds in 4WD Hi. I had the bed loaded with firewood, and chalked up the odd handling to the weight. Until I turned into the gas station, and got the loping in a sharp turn.
Now I can smell the lovely smell of axle grease. A casual inspection showed no leaks. And the 4WD still works fine. I’m just worried I caused damage. At this point, do I leave it be? Flush and fill the difs? Sacrifice a goat?
I look to the great mechanics of the SDMB for some advice.
You prematurely aged it, that’s for sure.
When driving on slippery surfaces, the wheel slip is the ‘give’ that saves the diffs…but when there is no wheel sleep (hard grippy road surface) and the wheels need to turn at different rpms, other parts (diifs, etc) give and wear in the process.
I don’t think the manual ever calls for a diff fluid change.
Everyone does it from time to time. The way I see it is that 4wd is so underused on most 4wd vehicles (DO NOT CHIME IN WITH AWD or Full Time 4WD stories) that you may never live to see the end of the diffs (hopefully).
Bummer. I live in Minnesota. 
I’d guess that if you had felt the diffs at the gas station, they would have been pretty damn warm. I’d flush and refill the diffs, and look to see if there was any obvious damage to the gears while the covers are off. I’d guess that there might be small metal filing in the oil if the gears wore much, and that would be a problem if they made it to the bearings.
Good news: Nothing that money can’t fix.
Bad news: Lots of money.
Good news: You can just fix the rear first.