GM 14-bolt FF Rear End with 149k miles
Hi to all, Our TV is a GMT400 1997 GMC K2500 7.4L Burb with 149k miles. It is 8-lug, 3.73, GVWR 8,600, with GAWR RR of 6,000 lbs for the full floater rear axle. We believe the rear end also has 149...
Forum Discussion
JIMNLIN wrote:
I had a new '91 2500 chevy with the GM 10.5" 14 bolt corporate rear axle with the G80 option. The owners manual and GMs service manual says no LS additive. Well the first 2000 miles the rear axle banged and clunked going around corners. Back to the dealer to see what was happening. I showed the driveway tech both manuals and he confirmed no additive needed per GM.
We went to their axle mechanic and he says to have the fluid service folks put the LS additive in it. Doing so stopped the banging and clunking issues. I ran the truck up to 215k miles and no more issues as long as I put a additive package with each fluid change.
This truck was in commercial service for the first 150k miles of the time I had it so it had fresh non synthetic lube every 25-30k miles. Never tried a synthetic fluid in any of those older axles.
My 03 did this as well, out of warranty. I called Eaton and was told how to fix it. Put one wheel in dirt the other on asphalt and accelerate enough to get the diff to lock. Do this 15-20 times and then put the other wheel in the dirt and repeat. After doing that they said change the fluid. They said it is to deglaze the clutches. After doing this my problem was solved. They stressed not to add friction modifier.
