T-case troubles

[spav350]

I have an '86 F350 CC with a 6.9, C6, and BW1345 case. When you put the truck in drive with the t case in 2H, it'll move about 5 feet and pop out of gear in the t case. You put it in 4H and it does the same. When you put it in 4L it drives fine. So..... I took it apart checked everything and found a bushing to be a little wore. Not so bad as to affect anything. I then decided to just buy a used unit, tore it down and inspected everything and put it back together. Tried it again and the SAME THING happend. Any thoughts on what could be wrong other than two bad t cases???

[spav350]

Found the culprit to be the input shaft bushing. It was worn down smooth and was creating to much endplay in the input shaft to engauge bully when in high range.