Thought it was bad u-joints but not sure
 

I just picked up a 96 Jeep Cherokee Sport. when in 2WD and in gear, I can sometimes hear a tapping right under the gear selector. Also, when in 4WD it is making quite a bit of noise above 30MPH. I initially was thinking the u joints were most likely bad but when I crawled under, I am not so sure. Here is a link to the video I took of it: https://photos.app.goo.gl/n6HKeLM1s5APGGZW9 In the video, it looks like the u joints are ok but maybe something else wrong? I am wondering if potentially issues with transfer case and the front diff but I am hoping not.

Any thoughts or comments? I am still mostly a newbie when it comes to diagnosing so any help would be appreciated!

Thanks,
John

There are 2 u-joints and a centering ball (aka a 3rd moveable/wear component with needle bearings) at the end of the driveshaft that connects to the transfer case.

Take the driveshaft out (the two straps at the axle and 4 bolts at the transfer case side) and manually articulate the joints. If you can feel any roughness or hear any noise, they need to be replaced.

It's not tremendously hard to rebuild the front driveshaft, but u-joints can be a pain in the rear if you've never dealt with them before. The double-cardan joint (the one with the 2 u-joints and ball) is a little trickier than the standard u-joint, but definitely do-able if you are capable of doing a regular u-joint.

PatHenry, were you able to watch the video? Does the motion that it is making point to u-joints? From other research that I have been doing, it didn't look like normal motion for bad u-joints but maybe this is another symptom.

I was just trying to be somewhat certain before taking the drive shaft off but maybe I can't avoid it.

Thanks!
John

x2 What Pat said. Also might want to check the slip joint for any play as well, less likely but still worth checking before you go about rebuilding.

Looking at the video the free-play I see is excessive gear backlash, definitely not defective u-joints. Could be lost pinion adjustment, or it's simply worn.

Forget the video.

Get under the Jeep and start wiggling stuff around.