I've got a 2001 Blazer 4x4. It's making a clicking noise that sounds loudest at the front passenger side. It's a repeated clicking at a rate of maybe 8 or 10 clicks a second (though sometimes it's more stuttery than constant). The clicking only happens when accelerating going forward, or when braking in reverse. In other words, it seems like it only occurs when the front end lifts up. When I tested it in reverse, I got up to speed, shifted into neutral, and then hit the brakes, and it still made the same sound, so it makes no difference if it's in gear. It also makes no difference if I'm in 2WD or 4WD, nor whether I'm going straight or making a sharp turn in either direction.

Any ideas?

 

Sounds like a stuck 4wd engagement cable which has partially engaged the engagement collar inside the front axle.

 

OK, it's been about 6 months and I finally have a solution to this problem. Yesterday my starter failed on me. When I took it up to have it tested, the guy at the store instantly knew it was bad without testing. He showed me how the pinion gear was sliding back and forth on it's own, instead of the spring pulling it back. Then it suddenly dawned on me that this was probably what was causing the clicking. Accelerate hard so the front end lifts up, and the pinion slides down the shaft until it hits the flywheel, causing the clicking. I put the new starter in and the clicking was gone.

 

Wow... That is way out there! Glad you got it fixed and thanks for the follow up.