I have a 90 xj, that came with the 30 vac disco front & 30 rear. I swapped the axles out of a pre 90's with out the vac disc, because they were free axles, and it had a 44 rear with 3:54 gears. So I was pretty thrilled with myself at this point..... until I took the wifebeater on it's mayden voyage.... when I turn right, there is a horrible jumping and grinding, kindof like driving with different gears in 4wd on pavement, it also happens driving straight, when I let off the throttle. So, I put it up on jack stands, put it in 4wd, 1st gear and let it idle while looking around. The "catch" or whathaveyou, is enough to shake the jeep, and you can see the "catch" in the rotation of the passenger tire. I can put my hand on the tire, and it stops spinning, and the noise gets worse. I have taken the whole thing apart. Ujoints, hubs, gears, axles..... it ALL LOOKS HEALTHY..... what in the mothr fk! HELP!!!!!! man... I should have stuck to my girl jobs lol!!!!!!

 

Are the front and rear gear ratios the same?

 

Yes they are.