89 Xj tranny prob
 

When driving my 89 XJ there is a loud ZZZZZZZZZZZZZ sound mainly when decelerating. Auto trans and 4 wheel drive. I adjusted the 4X4 handle like the repair book says. I also replaced the tranny mount. It will drive fine then when I let off the gas it makes that sound. It will not stop until ypu pull over and put it in N Nd then select drive again. It seems to happen more when decelerating. I thought it might be slipping out of gear but its not grinding. I also changed the tranny fluid and filter. I can run in 4LO and it will not happen. It does in 4 HI. Is it possibly the linkage on the selector for the transfer case?

If you get the noise in 2HI and 4HI but, goes away in 4LO. Then it is a Transfer case problem not a tranny problem. Tranny is moving under all of those conditions. If it was the tranny, you would have the noise in 4LO as well.