NP205 Noise at high speed

[WhiteTruck]

I have recently installed a used but new to me transfer case. With the truck up on jack stands a metallic grinding noise can be heard at speeds over 60 mph. The shift linkage is tight and not rattling. I guess the next step is to take it back out of the truck and tear it apart??
Any comments or advice would be appreciated. Thanks

 

[nvrenuf]

What t-case was in the truck before? If it wasn't a 205 you might be hearing a driveline vibration created by the driveshaft changes. If it was previously a 205 then I agree with the tear down, I've heard that if the center idler shaft is improperly set up (it uses shims) or if it has bad bearings then it can cause a noise/vibration.

 

[m j]

did you apply any lube to the coupler between the tranny TC?

 

[WhiteTruck]

The truck previously had a TH350 and a NP203 with 1/2 ton axles. Now I have a freshly rebuilt TH400 and the noisy NP205. Rebuilt axles, Dana 60 and 14 bolt, new rear drive line etc. The truck has 5-6" of suspension lift and I do not see any interference with the u-joints on the rear drive line, the front drive line is on the bench.