Hello,
I have a 99 s10 blazer and I just recently aquirred a vibration in the front drivetrain it starts at about 35mph and is constant up to highway speeds. When you put the vehicle into 4wd the vibration is way less noticeable, I checked all the 2 u joints on the driveshaft and the one on the transfercase shaft and none where seized up and seemed to move freely. The vibration seems to be coming from the pass side, could the inside joint of the cv shaft be bad and is this a common problem?
Thanks for your time.

 

It' might not necessarily be the u-joints or cv shafts. Typically when those start to go there are other noticeable things that come with them. It could be tie rod ends or even wheel bearings.

 

all the suspension componets are all tight the vibration feels like its coming from the transfer case or the front diff area but more pronounced on the pass side

 

Well the noise went away last week until I put it into 4wd yesterday and now its back. I'm starting to think it may be the front diff cable is not moving up and down fully causing the front diff to be half ingaged and not ingauged. I'm going to take a look at it this weekend.