I am traveling from Utah to N.C. with a load horses and noticed under the load there is a poping noise in the back end of my pickup. It only pops when hooked pulling a load and it happens when I am completly stopped then start going. I am usually good at finding the noise but this one is hard to pinpoint. I dont know if it is from my rear diff or if it is the tranny. I have put new universal joints and put air bags on and don't this is the problem. Any ideas?

I have had the same thing happen to my 2003 duramax and a 2001 2500HD w/ 8.1L. I found that it was the driveshaft yoke needs a special lube that only GM has. And I found out that GM has a bullitin about this and will fix it for you. But they don't advertise it. Hope this helps. The pop only happened when you stop and then go again, then it will pop.

Thanks for the info I will defintly check it out.