08 Rear End

[ssierra08]

I have an 08 sierra with a 5.3 and limited slip rear 3.73s. It blackbear tuned and has a vette servo. The truck has about 20k on it but seems that the rear is whining pretty bad. It whines under gas only. Is this common

[Jsdirt]

Usually a whine either on or off the throttle is due to incorrect pinion nut torque. If my memory is working correctly, a whine ON the throttle says the nut is too tight.

 

Why this would even be an issue on an '08 with 20K is just baffling .... tune or no tune.

[gmtech4]

its common if the veh is abused ,do you drive it hard?

 

get it diag'd by a pro to be sure

[700 sportsman]

Definately not common, you definately need to go through and check all the specs. (pinon depth, nut torque, etc., etc.)

[rrraider]

I have an 08 sierra with a 5.3 and limited slip rear 3.73s. It blackbear tuned and has a vette servo. The truck has about 20k on it but seems that the rear is whining pretty bad. It whines under gas only. Is this common

 

I'd go ahead and pop the cover for a visual; easy to do and it wouldn't hurt to put new oil in it anyway. I think you are going to find that you have some amount of scoring on the drive side of both the ring and the pinion, ring will be easy to see. Also look for an excessive amount of particles in the oil and on the magnet if it has one. If no damage is noticable I would still do a pattern check while I was in there. It's easy to perform and you can do a search on set up patterns for ring and pinion gears to see what it is supposed to look like. The proceedure, if you don't know, is to smear a bit of oil paint (artist supplies tube and preferably yellow) on a few of the drive side ring teeth, then have a helper hold tension on the drive shaft while you rotate the axle in the forward direction. This will leave a good pattern on the ring and the pinion tooth faces so that you can compare to what it is supposed to look like. If it's off but the tooth surfaces look good, I don't see how this is possible after 20K with no noise; the gears need to be adjusted.