I believe that the reason pervat said don't get a 97=98 axle is that they use 12 mm wheel studs, but if I'm not mistaken, so does your 99. It's the 2000 and up that use the 14mm studs. If that is correct (I believe it is) then I see no reason why a 97-98 axle wouldn't work fine. Both will be 8.8 and not the bigger later axle. 2000 is also disc brakes in most cases. He absolutely correct with the H9 code for the posi axle. (just read where he said 97-8 with discs on the rear. didn't read it close enough, but the info still is the same)
Your front differential doesn't drive the drivers side wheel from the factory. Actually only a max of 3 wheels will pull on a 4x4 and that's with a rear limited slip. Your rear axles (2) and the right side front axle are the three drive axles. The front can have a locker put into it, if you want to spend the money. That is the only way you will have true 4x4. It really affects the way you would drive and the feel on a normal roadway, so that is why they don't come that way from the factory.
Last edited by akdoggie; 03-26-2013 at 05:15 AM.