I just bought a 95' s10 blazer that had been sitting for about two years. I figured that it would require a little TLC, so after replacing the front right hub assy., pre-cat o2 sensor and a tune up-i have a roaring noise that only roars in 2wd high. the noise seems to be intermintent. I thought that it may be the right fr. tire but after rotating to the rear, the noise continues. even at very low speeds. if in 4wd, the noise seems to stop, there is also a popping that is intermintent coming from the left side front, which occurs when I press the brakes(intermintent) or when I take off. Also when the vehicle is parked, and I close the door-the pop may happen. The pop has progressively gotten worse and I fear that the roar may cause the wheel hub to go bad again. I have read some of the older post regarding the axle bearing and the vaccum issue from under the battery tray. About to check the vaccum line to see if there is any suction. I also saw that the front diff. fluid was bubbly. Now when I had the vehicle tuned up-they did say that they drained the old fluid, ran a cleanser through the diff and refilled it.

 

Sounds like the same issue (the roar) I'm having. I'm thinking right now the springs in the 4X actuator system are fatigued and are not keep it disengaged completely right now. Take at look at your actuator and line (under the battery tray) and see if you have any vacuum when in 2 Hi (you shouldnt't).

The poping sounds like maybe ball joints are dry and need to be replaced?

 

I checked the four wheel drive actuator under the battery tray and there was no suction-very difficult to check for vaccum with the battery still connected. But I managed; the only issue is the retainer clip that was on the line got bent in the process and in the attempt to bend it back, I lost it somewhere under the hood. Having trouble finding this part, as it is only sold with the actuator itself. -HELP-. The lower ball joint on the driver's side, however did have play and in fact did need to be replaced. I read a post that said that you should replace them in sets? Still clueless on the roaring on the passenger's side- after checking the wear on the tires(potential alignment issue), I saw that most of the wear was on the outside, but for the most part the wear was the same on both sides. Little help on this issue and I may be good to go-until the next project presents itself.