Drivetrain noise

Noise in all gear (trans & t-case). Not a grinding noise, a rotational noise.
Noise increases with ground speed. Noise goes away under accelaration (Torque applyed) in 4WD only. Have disassembled and inspected the 242
t-case, d30 front axle (did not dissasemble pinion shaft but it is not loose), front (stock) & rear (Tom Woods) driveshafts. No problems found.
With front driveline installed the noise changes pitch with bumps at highway speeds.
With the front driveline removed the noise is constant, no change in pitch with bumps at highway speeds.
Could I have a stretched t-case chain?
I could not tell if it is stretch by looking at it.

A long shot, but have you checked the wheel bearings? I had a similar noise, and it wasn't obvious for a while where it was coming from. It's possible that because the wheel is pulled forward a little in 4WD, it might change the pitch or intensity of the noise then. In my case, the noise was not the usual grinding from a loose bearing. The bearing was tight but the race was pitted, and it set up a buzzing vibration that seemed to be coming from the drivetrain. As I say, it's a long shot, but worth a look.

Thanks, I will recheck the wheelbearings.

The problem was that the front carrier was bent. Had to replace the carrier and gears.
This repair was done 06 or 07. no more drivetrain problems.