I was chasing a driveline vibration in my 2008 Aspen 5.7 AWD 146K miles. When I replaced a leaking rear pinion I put new U-Joints in the rear driveshaft to tighten things up, even though I found no real failure with them beyond age/miles. This did take my driveline vibration from random to more predictable. It now appears consistently between 67 and 70 MPH. I then was in for a transfer case shift motor replacement, because of failure to change modes or return back to AWD. While in there, I was inspecting the front prop shaft and could find no damage or obvious rotational play. I decided to remove the front prop shaft for a better inspection and this lead me down a more involved road of driver's side catalytic converter removal to gain clearance to remove the prop shaft. Then I found longitudinal (front to back) clicking in the CV joint with about 1/4inch movement. I ordered a new prop shaft and replaced it along with the shift motor. Previous owner had indicated the transfer case and differentials had recent fluid changes but this was questionable when the rear had new fluid and the front had old nasty fluid. So I decided to do a drain and fill on the transfer case. Once I drained and refilled the case, I looked at the fluid that came out. The quantity was correct at nearly 2 quarts. It was a little dark but overall not too bad. The real concern came when I poured the old ATF+4 into a jug for disposal and found some sparkly debris in the catch pan. There were no chunks but enough sparkles to make me pause.

I have driven the Aspen about 200miles since the repairs and I find the vibration is still there but has lessened significantly in intensity. It went from annoying to mildly noticeable in that same 67 to 70 MPH range and I feel a little again above 80 MPH.

There is no grinding or other noises coming from the transfer case but the metal sparkles in the oil have me concerned. At this point, I am guessing my driveline vibration is most likely in the transfer case. What would be the typical failure in an NV244 AWD transfer case with these symptoms and concerns? Should I just drive it until it fails completely, rebuild my unit, get a rebuilt or try and find a lower mile used one? How hard is it to get the transfer case out of the truck? It looks like there would be minimal clearance between the transfer case and the crossmember right behind it. I looked on YouTube but didn't find anything for Aspen or 2nd gen Durango for removal or rebuild of the transfer case. Thoughts?

 

first, oil analysis will always be your friend in cases like this. as a rule any used car I buy I send off samples of all wear fluids to see what the condition of things are.
they can tell you how badly contaminated the fluid is with Forbidden Glitter, especially if they estimate it to be the OE fill.
if you're concerned, I'd pull a sample of fluid after some miles and see what analysis says.

 

Thanks for the idea. I have heard of UOA but not had one done before.

 

https://www.blackstone-labs.com/