My TC(I believe) grinds sometimes when put in and out of 4H/4L. It also just knocks itself out of 4H about halfway into 2H, as well as 4L into TC neutral. Any ideas? Linkage? Trans and/or motor mounts? All are around 8 years old
The first thing to do would be to check the fluid level. The next step would be to disconnect the shift rod from the tc arm and see if you can manually shift thru the modes by hand.