t-case locked in 4H
 

We are running a dual case setup with a 470 gear in the back case. The shifter in the back case gets stuck in 4H. The shifter looks like it would be in 4 high but in fact it acts like 2 high. Every time this happens we have to pull the shifter, move the selecting forks forward and reinstall it, then it works again for a little bit. It sounds crazy, but we did try turning the shifter around so that it faces away from me. This resolved the problem for only a short window. Any help would be greatly appreciated. We have been fighting this problem for weeks. Oh also, we have had the case opened everything looks great. The shift forks have been measured and do not need to be trimmed. Also, reversing back about 10 or so feet does not resolve the issue either.