Hey everybody, the car is a 2001 n/a xj8 with 180k miles. I had to replace the a-drum with the clutch pack and o-rings, pressure regulator, c-drum bearing. The transmission shifts smoothly but shifting back from overdrive to 4th is very harsh. Regardless of the rpm it bangs into 4th gear. Shifting up is silky smooth all gears, even overdrive. Anybody experienced this before?

 

Did you replace the friction plates and clutches of the 5th gear (not overdrive) as well? If your A drum broke/snapped and you carried on driving, then littLe particles will be in the plates. These also disturb the correct function of the hydraulic actuator in the transmission.