nah u joints go out with hella vibration most the time..i have a 03 4x4 and think you guys are crazy lol where im from we get tonnes of snow and ice and the reason i can think this is happening to you all is..you all have LS? open diff? if its LS then the second wheel is kicken in if not then well your open diff 1 tire is spinnin..keep in mind how light our trucks are it doesnt take that much snow ice water anything to make it lift a lil in are already super dooper light rear end..that or get your foot outta the gas haha.. i know what your talking about though and its just the tires spinning from losing traction..get some mudders with big lugs so you can hear them spin and go try it bet youll hear the tire spining..
89 S-10 Blazer- SOLD
00 Honda Civic- too many mods to list..mm turbo..
01 Acura EL 1.7- SOLD
02 Edge 3.0 - SOLD
03 FX4 Level II - SOLD
03 PSD lariat 7.3L- Written off ( RIP 03/15/09 )
03 PSD lariat 7.3L- bought 04/06/09