my jeep is a 2002 tj, 4.0l, 5 speed, 4" lift, 33" tires, d30 spartan locker. last week, i was going through a round-a-bout in 3rd gear and heard a clunking/knocking noise coming from underneath around the tranny area. i placed it in neutral (noise went away) and i slowed down. i then downshifted to 2nd and released the clutch and the noise came back. so i pulled off the road and stopped. when i shifted to 1st and released the clutch, the noise returned. so i had aaa tow it back to my house.
when i got home, i drove down my street. 1st gear with clutch engaged and noise was there. i shifted to 2nd, noise went away during the shift but returned once in gear. the noise frequency is based on vehicle speed, not engine speed. so i tried starting in 4th, and the noise was still there. throughout this troubleshooting, with the clutch depressed i noticed the noise was a 2-3 on a scale of 10. when in gear and clutch released, the noise was a 8-9.
the driveshaft u-joints look okay and so do the axle u-joints. i'm leaning towards u-joints or axle bearings in the front. i plan on changing the clutch since it's still the original one with 87k miles, so that will give me a chance to checkout the tranny and t-case. any help is greatly appreciated. thanks.