I have a 99 4x4 I noticed today when I had it in 4 high when im off the throttle but still moving I can hear a clicking sound from the front. Doesnt do this in 2wd just 4. I cant see anything out of the ordinary when I jacked it up I changed front diff fluid about 5 months ago and havent had this happen till today any help would be great!

 

Could be a bad u-joint on the front driveshaft. If it was a CV joint on the halfshaft, it would likely do it all the time since they turn all the time. However, the driveshaft stops in 2wd, but, of course, turns in 4wd. That's where I'd start.

-Joe

 

I would look at thew CV joints too. In 4x4 they are under load and will click. When in 4x2 there is no load so they are less likely to click. Does the clicking vary with road speed?

JMC

 

Yeah when im on the throttle i dont notice it. But when Im off the throttle i can hear like coming to a stop.