falconbrother wrote:
I had to have my differential rebuilt. I jacked it up in the rear, started it, put it in drive and the rear end was making a swishing kinda sound. I pulled the half axles and replaced the outer bearings (labor intensive but, cheap) and that didn't fix it. So, I took it to my mechanic and he replaced everything back there except the hog's head. Not saying that's your noise but, it's worth checking. If it is shop around for the price on a repair.
Sumo Supersprings are pretty cheap and an easy DIY job. I highly recommend them to flatten out the ride. It took me about 20 minutes to do the left side and about 5 to do the right side.
You don't need to pull the grill to see if you have the GM transmission oil cooler. It's located dead center and is over the bottom half of the radiator. You can see it in there without pulling the grill, although that's a super easy job. There's a youtube video on it. Heck there's a youtube video for almost every possible repair on, Yukon, Suburban, Tahoe, Sierra, Silverado.. I may still add the extra cooler but, I have already towed the RV a number of times and never noticed that the transmission was suffering. Based on the mileage and looking at the hardware I'd make an educated guess that mine has been rebuilt. It's tight and runs great.
Took a quick look through the grille this morning. I have a transmission cooler - hooray!
The Denali package comes with an AWD drivetrain with its own fancy-pants ($$$) transfer case. Being AWD, it's difficult to troubleshoot this monstrosity with a jack and jackstands. I have a buddy with a lift, and that might shed some light. The noise is prominent if I just barely give enough throttle to maintain highway speed. If I coast downhill in neutral and rev the engine up to that same RPM, there's no sound. So whatever's making the noise, it happens only when it's in gear and under power.
I called SuperSprings tech support and spoke with Andrew. I asked if the SumoSprings would work on with the AutoRide air suspension. He said as long as the compressor adjusts the static height to be *above* the contact surface, it should work. He said once I get my trailer, hook it up and get the weight distribution calibrated, run the combo to let things settle in, then take a measurement of the gap where the SumoSpring would go and call him back.
