I just picked up a 2000 cherokee, all stock, 126k, 4.0 auto..... It has a slight vibration that you can't really notice until above 50mph... it's seems to be worse upon hard accerlation between the range of 20-40mph.... but when cruising it drones in the cab... I also cannot pinpoint of its front or rear... any troubleshooting tips would be appriciated,.

 

Tires,u joints, axle u joints,hub bearing all need to be checked .

 

I'm thinking its axle u-joints... tires are new (gonna have them rebalanced) there no play in the Hubs when I jack the front end up and push on the top/bottom of tire... any info how to check the u joints

 

You can just man handle the u joints to check them. They should not have any play in them. Also make sure all the caps are in there. You can pull the wheel off, but I just check mine by sticking my hands underneath, as long as they are firm you're usually good. THOUGH: They could be dry grease-wise which can cause bearing bind, but that's harder to check.

If they are greaseable, pump some grease in and see what happens.

Mine were bad, one was missing a bearing cap lol. It's not the worst thing to replace, it takes a few hours to pull the front end apart and then you are good to go for years. I'd replace them with the Spicer greaseables that go through the main body, not the grease port in the cap. Mine are at the cap, and they suck.

 

so I replaced the u joints, hubs, and rebalanced the tires... still vibrating... however the tires have some dry rot in between the tread.... could dry rottes tires be my culprit