DJDRAGON

98 tj sport, 4.0 ax15 np231 150k same issue. Recently purchased it for my nephew so he can trail with us. Drives fine, shifts fine. I'm 40yrs old and have been an auto tech my entire life but have never encountered this exact issue before. The only time it makes any noise at all is in reverse during deceleration or coasting. (2wd/4wd makes no difference) Under power in reverse it is fine. Pushing in the clutch does not stop the noise while still moving in reverse, only shifting the trans to neutral will stop the noise. And yes, it's definitely rotational noise, loud enough to hear from a good 50yds away. It didn't have the noise when purchased. I had to rebuild the front cardan and a front axle joint anyways when we got it so I replaced them all since I had it at the shop. We noticed the noise one day when he was trying a slippery hill that he ended up backing down several times. We crawled under it and everything is fine with the ujoints and mounts. No excessive backlash. He's only 16 and drives it everywhere. Almost 10k on it since noticing the noise, still drives ok, just that noisy tick in reverse as soon as you let off the gas. Spring has basically started and that means it's tire changing season here in upstate ny so I've been too busy to get him back in the shop when he and I are both free(you know how 16yr old boys are lol) Personally I think he was beating on it and miss-shifted or something and chipped some teeth on the reverse gear. When I do get it in the shop I'll stick a stethoscope to the trans and tc to decide which to tear apart. I've asked all my wheeling buddies and coworkers at the shop and found no tsb's about it in mitchell. I just spent the last hour searching the web and there's one post in pirate 4x4 about the same coast reverse noise but no one there actually addressed the question lol. Typical. Sorry this is wordy and long. If anyone has input I'm all ears. I'll update as soon as I can get the kid out of it long enough for me to take it to work to diagnose. :-)