Posi traction Problems

[zo6freak]

I have a 2002 silvy with the posi (G80) in the rear end. i notice that when ever i go over speed bumbs quickly i hear a loud grinding noise for like a split second and then its gone. well i just took a camping trip and i was off roading on a dirt road going about 10-15MPH and when i go over the bumps, my rearend starts grinding so bad that the only way it will stop is if I stop the truck. this happened probably 20 or 30 time on the way down the mountain. this noise cannot be overlooked it is a major issue and i was just wondering if any of you guys had an idea whats messed up. or if any of you have experienced this. i cannot tell you how embarassing it was to be basically crawling down a dirt road that i should have been goin 40 through. i even got under the truck to see if something was logged in the axel or anything and there was nothing.

 

sorry for the novel

 

 

-mike

[2003 LT Tahoe]

I have had minor lockup problems with my G80 when making sharp turns at low speed on a wet surface. I was told this is normal operation by my local dealer. However an independant shop said it related to a breakdown of the viscosity in the oil and changing the rear diff fluid would correct it.

[asilverblazer]

Sounds alot wirse than a fluid change fix, but it sure wouldn't hurt to try. When it drains look for metal particles, shavings, (which are respectively normal operating wear) or in your case large chunks. (which are not.) With over 100K on my fluid when it was drained was dark charcoal color vs. clear for new. And the magnet was very hairy. So the amount of metal is subject to mileage and use. Just telling you so if you drain i and you've got 200k miles on the fluid and it comes out black you won't freak out, but if we are only talking 10k miles and the fluid is black could be a different story.

[facn8me]

Just throwin this out but what about the parking brake shoes? Been known to grind. Tough to guess from here.

[GMCMan4.8]

A buddy of mine had a 2000 GMC heavy duty that made a grinding noise every so often when making a turn from a dead stop. Dealer 1st said that a fluid change was suggested They ended up looking at it & there was barely any fluid in the rear end. Likely was not topped off at the factory, because the truck was not very old at the time. So maybe having a look at the internal parts of yours & doing a fluid change would be a good start.

[mcmlxv]

At 500 miles, my '04 K2500HD began making a griding noise from the G80 rear locker when I accelerated from a dead stop, especially when making a right turn. My service department installed a GM synthetic rear end lubricant. The problem is, for the most part, resolved. The GM tech at the dealer told me that he sees this problem occasionally.

 

Hope that helps.