BACKGROUND - I have a 1994 Chevy S-10 Blazer with 4x4 on the fly. It has 233,500 miles with a 4.3 turbo engine. Overall, the truck runs great. I just purchased the vehicle a few months ago for $800 and ran it through inspection. It needed only a few minor repairs that my husband took care of (front passenger side upper ball joint, front driver side lower ball joint, rear shocks, muffler). We spent maybe $100 in parts.
PROBLEM - Since I purchased the vehicle in June, when I am driving and get to a speed of about 50 mph, the passenger side front starts making a high pitch noise. There is no difference in the steering when this happens. When I speed up, the noise goes away, when I slow down, it gets louder until about 25-30 mph, and stops with a " clunk.&Quot; When I had the truck inspected, the inspector did not even know what the problem was. He thought maybe the differential fluid was low. That was checked & the level of fluid is fine. I have asked every one I know who is a mechanic and they are not sure what the problem is either. None of them specialize in 4 wheel drive. Recently, when the noise started, I put it in 4HI (at 50-60 mph) and the noise immediately stopped. I do not know if it is stuck in 4HI or if it is engaging on its own and that is what is causing the noise.
SOLUTIONS - My husband was going to drop the front drive shaft (?) To see if it was a problem with the transfer case or if the hub assembly needed to be changted. After reading several posts on the site, it seems that I may need to replace the actuator. I do not have a lot of more money to put into this truck. The inspector said it was not a safety issue and was ok to drive, but I have a 3 month old baby and do not want to take the chance. Also, winter is coming and I would like my 4 wheel drive to work before the snow comes.
Ther were alot of problems with the actuators in those. Good place to start.
November, 11, 2007 AT 9:28 AM
I have the exact same problem with my 94 S-10 Blazer 4x4. It has 279000 miles and has been making the noise for about 8 months now. I had checked everything except inside the front differential. I tore it apart yesterday and found as bearing in the driven shaft that is dry, rusty and worn. It makes sense since that is the only bearing in the axle that would spin when it is not locked in 4 wheel drive and not spin when it is in 4 wheel drive(hope that makes sense to you). I have did a lot of searching and so far the only place I can find a replacement is through a dealer and then they only sell the complete driven axle with the bearing. I cannot see where this would cause it to not be drivable. It is just annoying. It looks like the cost for the part is around $220.00. I will let you know if this fixes the problem when I get it back together.
Update: I lubed the bearing and re-assembled. Noise is gone.
November, 13, 2007 AT 9:11 PM
Did you replace the drive shaft, or the differential?