2001 2500hd 4x4 grinds while in 2wd high

[cdub2010]

A new to me 2001 2500hd with a manual shift 261hd I assume. Drives fine in 4hi and 4 lo, but when case is in 2 hi it grinds. The transfer case shifts fine it doesnt grind while shifting just whne the truck is moving forward. I have only shifted while stopped with the clutch engaged, not on the fly. Im wondering does this sound like a transfer case problem or an axle acuator problem? Never had problems with any thing newer than an 87 4x4.

[57taskforce]

My father in law had an 01 2500HD with the 8.1 and 263HD (electric shift version of the 261) case. His did what you are describing and I had to do a full rebuild on the case unfortunately. I’d change the fluid and check it real close for metal.

[Second Series]

Does the axle actuator disengage in 2wd? I may have had a similar issue with my '90 k1500. The 4wd didn't work one day, after ohming out some wires I replaced the actuator switch in the t-case. I was getting some binding in 2wd, not grinding. The new switch was bad, replaced it again and all was well. I took an ohm-meter to the parts store and tested the new switch there.