[NHwheelin]

My buddy has a 89 with the ax5,np231,d30,d35. When he accelerates or is just cruising he has a loud humming coming from under the Jeep. As soon as he foot is off the gas it goes away. We have replaced the universals,replaced the rear diff fluid. He noticed he was low on tranny fluid the other day so he topped that off. He said the noises isnt as loud now but it is still there. So I guess I have two questions. 1)What might be the problem? 2)Will an ax15 from a 94 swap right in place of the ax5? O yeah he has the 2.5 or it might be the 2.4 not sure what year the switch was made buts its the four banger.

[sitdwnandhngon]

Might be a pinion or carrier bearing on it's way out. Or maybe the pinion nut worked loose a little bit. It happens on my front ds from time to time because it's unbalanced.

[bunkrdfool]

Same thing happened to me. I noticed a loud humming noise coming from under. and it was because my drive shaft was a little wobbly because the pinion nut had become a little loose

[NHwheelin]

I figured it would be something to do with the rear axle. I thought it might be the pinion bearing but it only happens when on the gas. I will have him look at the pinion nut tonight. I hope thats it cause I am tired of swapping tranny,s from vehicle to vehicle