I've got a 96 Cherokee w/ 115k, and my mechanic who I generally trust is telling me I need both front u-joints and axles replaced.

As a guy who's generally handy with replacing alternators and water pumps and such, can yall tell me what I need to look for in these pieces when I get under the truck to make sure they really are probably going bad and that this expense is warranted?

Thanks. I really do appreciate your advice.

Damn! If it needs all that it must be shaking like a 300 pound belly dancer!
U-joints need replacing when there is ANY sideways movement in them. With the vehicle in neutral and the park brake applied you get under there and push-pull-shake-anything you can to try to get any small amount of movement on the joints.
If ONE of them hs even a little play in it then you replace them both.
For the axles it is the same. But harder to observe. I just replaced the axles on my Ford Ranger. They were available at the local parts house (order only) for $63, each side. They were new aftermarket parts.
Unless you have driven it with vibration for a long while I wouldn't expect all of them to go out at the same time.
Big Jim <img src="/forums/images/graemlins/pfft.gif" alt="" />

When your mechanic said "both front U-joints", he probably meant the front and rear U-joints on the front drive shaft.

When he said "both axles", he might have meant that the U-joints on both the front axle half-shafts (left and right) also needed to be replaced.

I highly doubt that both axles (front and rear) need to be replaced.

I'd suggest that you ask your mechanic exactly what needs to be replaced, and then get back to us and let us knowwhat he said.

so, I have a obnoxious shimmy in my 1991 Cherokee that has 200k on it...I now have new tires, new shocks ( 5 yrs ago but the car sits at an airport) new brakes, rotors, Poly bushings in the sway bar etc. New steering damper, new steering link, etc.
I still get this shimmy at about 60-65. It comes and goes. It may start under load or go away in a corner. Im tired of it. Could it be U JOINTS?? They are probably original joints....this was my moms jeep for years and then it sat in the barn for a few years. Ive replace the pan gasket, front seal( has a speedy seal on it too) timing gears and chain, electric brake pump and hyd. accumulator, rear seal, rear axles, bearins, seals , bla bla bla . Tis a nice solid jeep that always had AMSOIL in it.

Oh, Just put a dynomax cat back muffler and pipe on it sans...converter. Gets up and goes and sounds great.
I have a shop on my property and a lift so it helps when running old vehicles.

1991 Cherokee limited.

s

From your description, there is a high probability it is u-joint related.

There are a couple of other things to check...

As noted in this tread, the axle and driveshaft u-joints are fairly straight forward to diagnose. Looking at the end caps, if you can see signs of rust, replace them. If they have grease fittings and you cannot add grease, replace them - especially if they are original. If you have recently replaced them and cannot add grease, you may have a plugged zerk fitting.

Also, check you steering linkage - specifically, the tie-rod ends where they connect to the steering knuckle on the axle assembly and where connected to the steering pitman arm. The tie-rod ends are hardened steel against a cast steel tapered fitting. They do wear and loosen with mileage.

Yes, it is a solid jeep. I had an 89 Cherokee for a number of years and loved it.