So I have posted about this before, but just wondering if anyone has experienced this issue and found a solution. My Cherokee is totally stock, with no lift. It starts around 40 mph, pretty noticeable by 50 mph. At 70 mph, it kicks in hardcore, to the point I won't go any faster. New tires, and have tried a replacement ft driveshaft with no improvement. If I remove the ft driveshaft, it totally goes away. I pulled the axle shafts, and the u-joints are fine. I'm at a loss. Any ideas?

 

check the front pinion for play at the diff and also check the front output of the tcase sounds like a bad bearing somewhere.

 

Yeah I suspect the shaft is transmitting something, like a tuning fork. Nothing obvious though, no play on either end. It's worse when applying throttle, and seems better when towing my snowmobile trailer, oddly enough. I agree with what you said, but how else can this be checked if nothings loose?