alright well within the last 2-ish months i have been hearing a whomping noise coming from my rear end as i drove and the sound would always get louder and faster the faster i drove. and it started to worry me a couple days ago when it got ridicuously louder. i got the rear end off the ground and let it idle in drive and listened, my rotors are fine as well as the tires and brakes. i looked underneath and saw some fresh oil around the differential where the drive shaft meets the rear diff. and the whomping noise is coming from the drive shaft i found out. and i know that the seal is broken and i think the bearing may be shot too. but thats what i think, if anyone has any clue whats wrong please let me know

 

I'm having the same issue right now in my 89. When I had my 87 K-5 it happened too and when it went, it went in a glorious fashion, I'm just lucky I wasn't going fast. I actually had to hold the gas while trying to stop to keep the pinion angle right at the end. I wound up replacing the whole rear for 35 bucks because the dude wanted the thing out of his yard. I'm pretty sure mines a bad bearing as well. Not looking forward to it but gonna try doing it without removing the rear from the truck so I don't have to replace the U-bolts and all that stuff.

 

Same thing here, 97 blazer @ 189,000mi. Got it checked at Midas today & they gave me a $1,400 estimate for the pinion bearings to be replaced. I plan on just finding a another rear end at a junk yard.

 

well i found out what the noise was it was a wheel bearing but i do need to replace the pinion seal to stop some leaking, and may be the pinion bearings cause theres a whine i start to hear at about 35mph