13 speed eaton transmission not shifiting into high range?

Could be a number of reasons... air line which actuates the range selector might not be working, could be a bad shaft in the transmission.... you'd have to give a more thorough diagnosis in order to narrow it down. We'd need to know if the range selector switch will even flip up or not, and what happens when you try to shift into high range. If you've had the transmission serviced recently (especially if you've tried to DIY it), that would be pertinent to know.

We have repaired air lines 4 times with the final time we replaced those lines. We also replaced shifter. When I try to shift into high range, just get a severe grinding and have exhausted any ideas?