Volvo 760GL transmission going crazy

[Btblder]

I have a 89 760 tubo 4cyl wagon. Driving on the freeway or even in town the transmission upshifts and downshifts alot. When it's cold it shifts hard like right now wham. Had the fluid change and filters cleaned. Last night while driving down 101 here in San Jose, there was no power to the transmission I tried manually down shifting with no results. I coasted to an odd ramp where I tried reverse with no response car would not move in any gear. Had it towed to my house, this morning I thought I would try and move it no problem drove it around the block but I don't trust it so I parked it. Anyone have any answers, I checked the fluid and it's clean and full. Thanks