Hi ya'll, I just bought a 97, great condition, runs great, just needed reg maint, shocks, and front sway bar links. So I lifted the front end (jacked up by the bumper) put shocks and sway bar links in, simple right! Set her down for a test drive and BAM! WTHeck some howling whistling metal to metal noise came from under the dash which started at 20 mph and increases with speed, lift her off the ground entirely and run her through all gears-NO NOISE! While I was under her I did notice the manifold was cracked in half! Replaced that after the fact. Anyway all this logically suggests a weight bearing issue, replaced wheel hub assy's even though I had no wobble or issue (she really runs good but the noise is relentless). U-joints are strong and steady although I tend to do these tedious things regardless and have them ready to put on. Noise doesn't come from turns is same no matter what - acceleration into the wind. The T-Case was replaced in 2012, fluid good, I flushed the differential fluids, no metalic parts, color good, etc. I have ruled out drive train, off the ground I have to rule out transmission. I do my own work, typically, but after the eyes of a 5th mechanic which is baffled too I now pose to you the trivia of the day. Any ideas? Could this simply be an HVAC fan bearing issue as the sound comes from under the dash or could I have bent the frame? Bring it!