D17 Power Director Stuck in High

A buddy of mine has a Series I D17 diesel and he told me the power director is stuck in high range. I don't know much about power directors, other than adjusting them by moving the shims around, and I don't think he does either. What could cause this, and how could it be fixed? I know there's probably several different variables, but what are some probable causes? He and his dad want to eventually get the ol' girl all fixed up, and they're making some progress. It still runs good and drives, just only on the high side. 

Edited by CrestonM - 08 Jan 2017 at 9:10pm

I you verify that the handle is still coupled to the shaft going through the torque tube.   The early d17 has a bolt on the bottom that locks it to the shaft I think I have read something different on the later ones. Mine is a serries 1.
The shaft in the torque tube has two wood drift keys inside the transmission.   If those keys fell out somehow that could do it as well. You could drain the oil and check it through the side access plate.

Creston, I have the same trouble with my D-17 Series I except it is stuck in low range.  I know I have to take the side panel off and get a look in there and take some pics of it.  Then the guys can help on here if they see it.  SO, take pics when you get the side open and post them.  Then you'll get help faster and more accurate.
Good luck buddy!