I have a couple suggestions as to cause that may be overlooked. First. It is possible that the seal was not installed properly. Gm has and provides specific tools used for installation of seals. Good technicians find and use the proper tools. Bad techs use what ever they can find to pound it in. So it’s possible it was not installed properly. It also could have been hit by the axle splines when the tech was re installing the axle.
It is easy to overfill the rear dif on these. It is also easy to underfill. You have to put the fluid in with a machine and the machine pumps faster than the fluid can spread into the dif. So you have to let it sit for a minute and let it run out and settle a couple times. Should be even with fill plug and a small trickle of fluid come out of fill plug when removed.
I also recommend replacement of the vent as this often goes overlooked for the root cause of leaking seals.if it is plugged or obstructed, pressure can’t escape and can cause seal failure.
I was wondering if the vehicle feels like it binds at all on tighter turns?i would compare it to driving in 4wd on dry surface but not as aggressive. I’ve replaced electric clutch on these in the past where fluid has leaked out of the pinion seal and got into the torque tube where the clutch sits and when this happens the clutch won’t release properly. This can cause the dif to overheat.
The 3rd is the tires. What condition are the tires in. Awd vehicles all the tread should be within 3/32” of each other. If they are not they can load the dif up and cause gear ratio issues. This can not only damage the rear dif, but also the transfer case so I would also check the fluid in the t case for metal or evidence of failure.
The last thing would be worn bearings in the rear dif. This is the least likely scenario as they really don’t wear out and if they do there will be other evidence. When they wear out on this style dif it will affect the backlash and preload in the dif and there will usually be a lot of noise associated with that.
I hope this helps
March 26, 2018 at 1:13 am
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