My 92 dually 2wd frontend pops just about everytime I drive it. All the rubber bushings in the uppers look excellent and so do all the sway bar bushings and strut rods. I haven't done a ball joint check yet but I've had ball ball joints on other vehicles over the years and never heard any pops. Had a few people say that it sounds like a spring that's not seated but it doesn't have that 'ring' to it. The truck drives fine and the tire wear is good. A friend's truck does the same thing and still did it after he rebuilt the whole front end and this truck looks like someone has already done that. I pulled the large washers off the strut rods and the bushings look brand new and from what I can see, the lower control arm bushings appear to be ok. I've gotten used to it although it can be annoying at times but I'm also trying to sell it and well, you know how that goes.