'07 Ram not shifting on its own, will shift manually.

[Soonernort]

My Ram is a 2 wheel drive quad cab with the 4.7 160,000 miles. Yesterday it down shifted hard, then it wouldn't shift again.. I can pull it down and shift it manually up to drive it will not go into over drive.. It pulls fine and doesn't slip. I had the diagnostics ran and he told me it's saying shift solenoid A is bad. Any help?

 

[hotkarl]

Change shift solenoid A?

 

[Soonernort]

The code that displayed on the dash is p750