Vibration / Ratcheting when accelerating

[S1L1K0N]

Hey folks, I'm looking for some advice, or a link to some info regarding the front wheel drivetrain on my 2001 Explorer. Recently I noticed a slight vibration/thrumming in the steering wheel when under load at all speeds (right after getting my drivers side lower ball-joint replaced). Then last night, while accelerating I noticed a distinct tick,tick,tick/ratcheting sound.

My first thought was one of the CV joints, but after poking around here I'm thinking front drive shaft, as the clicking/ticking happens only when accelerating at medium to heavy throttle (from stop) and occurs while going in a straight line - the ticking will occur when turning, but again only when accelerating.

What I'd like to know is if it is safe to remove the front drive shaft? Will I damage the transfer case and/or front differential if it's removed for troubleshooting, also if the CV joints are the culprits, will they still tick/ratchet without the front drive shaft driving the differential? Is there a sure-fire way to troubleshoot the front drive shaft?

It's an 2001 Explorer, 4 door, 4.0L (SOHC) with 174,000kms (~110,000 miles), and the AWD gets worked out in the winter regularly (this is Canada ), but the truck doesn't go off road normally (it's the wife's ride). Thanks for your help!

 

[S1L1K0N]

After digging around a few threads I figured it was safe to pull the driveshaft off to see if the problem disappears, and it didn't. When 4x4 Hi is manually engaged, the truck seems to bind more than ever, I'm starting to think it's the transfer case. The ratcheting sound occurs whenever there is moderate to heavy throttle, going straight or turning, and it sounds like it's coming right from under the middle of the truck. Does anybody know what model year(s) of xfer cases are compatible with a 2001? Perhaps I can find one at a wrecker...

Incidentally, I think the vibration is from worn u-joints; one of the caps on the front drive shaft u-joint was kind of stiff, and the rear drive shaft looks to have the original u-joints - I'll deal with those later...