Whine only on acceleration

[Treypeaden7]

I have an 04 manual 4.0 TJ 180k miles and more than moderately off-road with it. A few months ago, it all of a sudden started making a loud whining/grinding noise from engine/clutch area when accelerating. Sounds almost like straight cut gears or a bad power steering pump but much louder.
Details: it only starts around 20ish mph and gets louder/higher pitched with speed, only makes noise when accelerating, sounds more like a grinding noise when barely pressing the gas. Goes away when coasting. Is slightly louder when under load (going up a hill). It is not rpm dependent at all. It seems purely speed dependent.
All fluids have been changed and no sign of damage. Rear axle, rear driveshaft, front gear, and transfer case has been swapped, and the noise is the same.
Where should I start next?

 

[reddvltj]

I have an 04 manual 4.0 TJ 180k miles and more than moderately off-road with it. A few months ago, it all of a sudden started making a loud whining/grinding noise from engine/clutch area when accelerating. Sounds almost like straight cut gears or a bad power steering pump but much louder.
Details: it only starts around 20ish mph and gets louder/higher pitched with speed, only makes noise when accelerating, sounds more like a grinding noise when barely pressing the gas. Goes away when coasting. Is slightly louder when under load (going up a hill). It is not rpm dependent at all. It seems purely speed dependent.
All fluids have been changed and no sign of damage. Rear axle, rear driveshaft, front gear, and transfer case has been swapped, and the noise is the same.
Where should I start next?

Just a thought.

If RPM doesn't make any change to pitch or volume then I would.concentrate on the things that can't change except with speed. T-case (output gears), differentials, and wheel bearings. Only making noise under acceleration points more towards a gear mesh issue more than a wheel bearing issue.