Okay guys, I looked over the results of a few searches however:

99 Cherokee Sport, Auto, 4L, 4x4, BONE STOCK:

The rear end shakes when at ~48 mph with gas applied.

1. I've looked over the rear driveshaft, the T-case output, the diff input, and the u-joints three times. All looks/feels/sounds good.

2. I slapped some new shocks on the rear for giggles.

3. The leaf spring U-bolts and connections look/feel good.

4. I had the rear wheels re-balanced at the tire shop.

On a side note: at the same time, she had a misfire in cylinder one, bad fuel injector; so I replaced it. Engine seems to run a little smoother now but the rear-end shake at ~48 mph still exists.

Any suggestions where to poke around next? Thanks in advance.

 

bad tire ,bent drive shaft ,bad u joints,bent axle,bent rim,bad wheel bearing...

 

Actually take off the driveshaft and pull the u joints. Sometimes they are bad but you can't tell by your own hand. Remember, the motor has a but more torque than your body can produce.

 

x2

 

Wow, I say the u-joints are good and yet people say "check the u-joints". I've done a gazillion U-joint jobs, trust me, their good.

I say the tire shop re-evaluated the tires and people say "check the tires". wow.

C'mon guys, read peoples' original post and go from there. Try to avoid posting quick 'typical' replies.

Just so you know, it's clutch chatter in the transmission.

 

Did you ever find the problem??

was it the differental? or wheel bearings?

 

Was a misfire in cylinder #1 (no compression) Harmonics were traveling down the driveline. I installed a new engine, no more shake.