I've had this 1994 K1500 for forever. It seems I have to replace the 4WD actuator every season, and every time I take the old one out, the rubber on it looks like a wrung out rag. So I feel there is something going on in there that is jacking up the actuator on regular use. Replacing the actuator isn't the real issue, I'm willing to do that every year or two, and it solves this issue temporarily. The real issue is, after about a month or two of use, the 4WD acts up... When I engage the 4WD, the 4WD works, however, unless I take off extremely gingerly, I get this loud popping noise in the front and I'm no expert, but it also seems like during each pop the 4WD disengages and re-engages. This popping is very rapid, probably 4 or 5 per second, and then once I get going, it no longer pops, until I have to stop and re-accelerate. It also makes this same severe popping noise when making a turn with the 4WD engaged. Upon my most recent replacement of the actuator, the new actuator didn't solve the popping. That's the first time a new actuator didn't solve the popping issue at least for a while.

Any thoughts on the cause of this are much appreciated.