I hear a howelling noise coming from my truck while driving. on 2006 GMC Yukon

my rear diff is new and that is not where the noise is coming from. i hear a whirring or howelling noise under acceleration and decell also.I jacked the truck up and placed tranny in neutral and spun the rear wheels turning the driveshaft and herd a dry brushing/squeeking noise from transfer case/tranny aera. the trans shifts good and has clean fluid. the truck has 100k on the clock.can you help me diagnos the noise ?

by in Franksville, WI on April 09, 2012
1 answer 1 comment
ANSWER by on April 10, 2012
YOU MAY HAVE A TRANSFER CASE ISSUE OR POSSIBLY A U JOINT PROBELM. SERVICE YOUR TRANSFER CASE A(DRAIN AND FILL) AND LOOK FOR METAL IN FLUID. AT 100K IS OVERDUE ANYWAY.
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COMMENT by on April 10, 2012
thanks i will do that and re post. i did have 3 tranny/diff pros drive it and they said nothing is wrong with t case. another guy told me the richmond gear set i installed @ 8000th backlash in rear diff could be the prob cause they are noisey gears by nature. pinon depth is mint off center line new aubern carrier and ALL bearings also.