Your truck has a n eaton locker with no plates so the last post won't work try the additive or change to royal purple or another fully synthetic that does't require the additive

Ok, thanks! I appreciate the input! will try and see if I can change oil and see if it makes a difference, keep the advice coming, and THANKS! to everyone for the help!

Royal Purple is definitely not going to solve your problem. That stuff is garbage, it used to be good but not any more. It doesn't even meet initial viscosity requirements. Not trying to start a holy war here, but......read this if you think its any good. All I know is, if you're going to put into print, info about a somebody elses product, you better be right on the money!

http://www.amsoil.com/products/gearl...hitePaper.aspx

I have actually had pretty good luck with Amsoil, and always used Mobil 1 for engine oil in "road" vehicles, I heard good things about Royal Purples "gear lube" for outdrives though, there is some good reading in that article, and, like yourself, I dont want to step on anyone's toes, but, the link is from the AMSOIL page, so, I dont know if its biased or not?

Either way, I appreciate all the info, regardless of what oil we use! LOL

How do you know? you would have to look up the build codes to see what rear is in it. My guess is that if it didn't chatter right away after the fluid change its probaly not that. I have seen many gm diffs start to do that around that mileage,including mine,02 2500 hd. I just started to notice it this week. I work at a toyota/gmc dealer so I will look into it and see what the gm techs say.

I would really appreciate that, Thanks!

This a common problem with GM truck locking rear ends. I too have been told by the service tech that it is the clutches. An easy way to "fix" the problem is figures 8s, both forwards and backwards - this was casual advice given to me by the service tech. I have done this and it relieved the problem.
130k miles and no serious issues.

It could be biased, but I think if it was, they would be in court quite a bit!!! Would you risk a defamation of character lawsuit just because you think you're better than the competition or you know you're better than the competition?

I go back to work this coming monday..... had some time off. in the mean time I think the figure 8's couldn't hurt. I'll give it a shot.

Figuer 8's as mentioned also a hard acceleration not enoght to twist them up but apply some force also a hard acceleration with the wheel cut one way or aother.
-Mike