Clunking front end in 4wd

[90rangersuper]

I got my 4x4 shift moter working thanks to you guys, now i have another issue, when i am running at any speed there is a loud clunk which seems to be comming from the driver side front end, occasionaly it will come from the passenger side, the clunk is so bad that the truck jerks when it clunks,2wd is fine. Today was the first time i had it in 4wd and as the day wore on it clunks more often. I have no idea when the last time the 4wd was used, i had the truck for 2 years now. The truck is a 90 ranger supercab, 4.0 with a 1354 electric t-case with auto lockers on it. I have no idea where to start with this one, gonna look in to the front end more this weekend. any help would be great. Thanks

 

[4x4junkie]

Probably the front axle U-joints and/or the spindle needle bearings are shot (it could be those auto hubs too).

I'd start pulling it apart and give it a once-over.

 

[michowski]

most likely a u joint like junkie said. I had that clunking in the front end and I changed to manual hubs and replaced a bad u joint and the problem was gone.

 

[85_bronco24x4]

Also check the control arms and bushings on the front end, I had a 3rd gen ranger 4WD and the clunking sound I had turned out to be the control arm bushings. Easy fix, very quick.