So I have a driveline noise. Yes, I've done some searching on this but wanted to run my troubleshooting efforts by you guys. Initially, I accepted my slack as typical Rover slack. At the URE Safari, a friend drove the D90 and said, "Yes, you have more than the typical slack." So much that while the t-case is in low and engine braking down a hill, if I push in the clutch I get a "clack-clack-clack" sound as the slack is played out. There is no rythmn to it, just as the truck surges, the driveline makes the clack-clack noise.
Additionally, I now have a harmonic noise that is present at 20-25 mph and at 30-35 mph. Not a terrible, imminent destruction harmonic, but a noise that was not present before the event. Once at hwy speeds, it is not apparent over the typical soft, quiet interior noise that allows you to have a nice conversation with your mother in-law.
Concerning the harmonic, I drove from CT to NC to get to the event. This is the most miles I've put on her at once. I religiously checked my fluid levels before and during the trip to make sure everything was okay. After the event, I changed my rear differential and my t-case fluid. No shinny stuff. No change in the noise. Transmission (R380) was changed about 15K ago using Royal Purple. Had a little hedgehog, but nothing chunky. I am not sure if the harmonic became present after driving to URE, or after the trails. The driveline slack has always been there.
I removed the front drive shaft today thinking that it may be the front differential. The slack got much worse. Harmonic was also still present. I did not pull off the PTO cover to check for the cross-drilled gear. Does this sound like a symptom of a worn spline? Is there a speck on slack? Degrees of rotation? Am I facing two different issues?
I am currently stationed in the Norfolk/Newport News area and would love to crawl under another D90 to compare some things. Thanks.