Remove the hose and check for vacuum at the modulator, you should have manifold pressure, about 18 to 21”; it’s located on the driver’s side middle of the transmission. No vacuum follow the line up into the back of the engine, check for a broken or disconnected hose/line.


With no vacuum to the modulator ALL shifts should be harsh. Another possibility is a broken K2 accumulator piston or K2 spring in the valve body.