rearend noise
 

96 blazer S10. Have alot of whinning out of the rearend. looks like it has a new tranny in it. all the u-jionts and d.shafts are good any suggestions? Could the gear ratio be off or what, bearings?

When does it whine?
Acceleration, deceleration, or maintaining a steady speed?

Thanks for the reply. I'm new at this. It whines the faster you go. It seems to be vibrating when going slow. Like the gears are meshing really hard, (ring and pinion) i don't know. The vibration seems to me to rule out bearings. Could it do that with the rearend gear not matching the tranny?

If the whine happens all the time, acceleration, deceleration, and maintaining a steady speed, and is speed related, it could be side bearings, pinion bearings, or as you mentioned, ring and pinion not meshing correctly. Noises can be difficult to identify, even with a trained technician. The vibration could be worn/loose pinion bearings, they can also cause a whine. The differential will need to come apart to determine exactly what the problem is, and repair it.

rear transfer case
 

96 blazer LT. iI look at the drive shaft and noticed that the tag on the rear transfer case says 272 ratio. Could that cause the whining noise that i hear?