Okay so I was greasing my front end today and during my check I noticed one of my axle shaft U-joints has a tiny bit of play (less than 1/16 in) I know I will have to replace it. Is the car safe to drive at freeway speeds for around 200-400 miles? I haven't noticed any clunking or odd noises while turning. U-joints themselves look fine I did spray some silicone on them because my mechanic said to do that until I replace them.

 

Probably not a problem since the axles just spin passively
and the u-joints don't do much articulating when driving in
a straight line.

Don't use the 4wd, of course.

Best to use Spicer 5-760X u-joints on the axles of a 98 XJ.
Go ahead and buy them now.

 

The axle shafts always spin with the wheels. If they are bad, replace them asap. If one comes apart, it can do a lot of damage. Ask me how i know

 

That's what I figured there's no noise at all just a miniscule amount of play enough to cause a little bit of shake at highway speeds. I'll get it replaced in a couple weeks around 200 miles locally, my shop is going to charge $225 with a wheel bearing.