'00 XJ front axle

U have a LP.

OK I'm new what's the difference HP = high pinion...LP = low pinion?

Is the Hp more desirable?

high pinion is marginally stronger and it has a lot better ground clearance.

Thanks...is that why when I looked at the skyjacker info on the 6" RR..it said it wouldn't work on XJ made after july 99...is that when they switched to the LP?

did a advance search on "hp d30" & "d30 HP" and didn't find a thing...not even this thread..hummmm! must be doing something wrong!

A HP axle from the factory were only HP dana 30, 44, 60. The driveshaft/output is about the centerline of the axle tube, whereas a low pinion, or standard diff is lower than the center line of the axle tubes. A HP ring gear is working at it's true rotation, whereas a LP in the front is really running in reverse, or on the "Coast" side of the gear. It has been said that a LP is giving up close to 30% of it's strength because in essense it is not running true. You cannot a axle upside down and get a high pinion the oiling deficiencies alone would give the axle a short life. Also a HP and LP have diffent cut gears. Hope this helps, a HP in the rear is the same as a LP in the front, running on the coast side.

Check out Crash's axle thread sticky, he breaks down all the axle tech in an easy to understand format and sets guidelines for gearing and tire size etc.