GM-GMC: 4-wheel drive noises, trailmaster suspension lift, wheel hub

Question
I have a 1998 GMC Sierra K1500 Z71 with a 4" Trailmaster suspension lift. It has a shift on the floor 4 wheel drive system and an automatic transmission. When driving in 2Hi and turning around a corner the front end makes a popping sound and feels like something is catching. Also, when I push the lever from 4Hi to 2Hi there is loud popping and grinding sounds coming from the front as it disengages and then the popping sound continues as it does in 2Hi. How do the hubs lock and unlock? Is it mechanical or done by vacuum? I have worked on cars for years, just nothing with a 4 wheel drive. Could it be something that I could possibly fix myself or is it best to have a service garage look at it?


Answer
There are no hubs on your vehicle.  The front axle drive parts turn continuously and four wheel drive is accomplished by locking the differential.

Your problem is likely a constant velocity (CV) joint at either (or both) front wheel(s).  The rubber boots crack and tear, letting the lube escape and dirt intrude.

If you discover a cracked or torn boot right after it happens, the CV joint can be repacked and a new boot installed.  Your problem sounds like the joint(s) have run too far without lube and require replacement.

It could also be a front wheel hub bearing (which are sealed and have no maintenance requirements) but it is more likely to be the CV joint(s).

Unless you are familiar with doing this kind of work, it is best left to a reputable shop.