do p 0123 and p 0783 together point to a common problem on a 98 jeep 4.0

Question

I have 2 codes p 0123 and 0783. Position control sensor and 3-4 shift.

I was on the highway today and I seem to no longer have a 4th gear at all. This is on a 98 jeep Cherokee Lorado, 4.0 4wd, with 130,000 mi.

Does this mean the transmission is destroyed, or can there a be simpler solution. It does just fine in town, and I had 4th last time I was on the highway.