I figure you have an AOD?
I know the tv rod adjustment is critical.
If the fluid is reading correctly, doesn't smell or look burnt it is likely not bad yet.
Abrupt shifting can be due to a few things.
Most common
in my experience is stuck valves in the transmission.
But I have to qualify this by saying I am a shade tree mechanic and I don't dive into autos very often.
So wait for better answers.
Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.