Transmission not wanting to shift after storage.

Slangy

Sgt. CulPepper
Location
Utah
44RE automatic transmission. Last year the Jeep drove great, not many issues at all other than I probably only put around 2,000 miles on it. Then I parked it in the garage for about 7 months without driving it and rarely starting it. Now I jump in, shift into gear and leave the driveway and start up the road, the rpms climb to over 4K and it won’t shift. Drive it for about 2 miles in first gear and every now and again it goes into 2nd, after driving down the hill from my house it coasts fine and seems to get into the proper gear after a few minutes, but other times I can go a few miles of the back and forth shifting and it won’t stay in a proper high gear.
Then it drives fine the next day, then the following day it’s back to the weird shifting. What I am asking is there something that would cause this after sitting for a period of time?
 
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