How is it better for going up hills?
Calibrate your rudder?
Increase the deadband o your rudder?
It's not a transmission issue, it's your twisty rudder that is the problem.
wrongway
First, Auto transmission climbs hills far better then manual - if you go one to many gears you get stuck, auto you simply just keep moving towards the hill, except for the T34/85 which has to go backwards up the hill - even in first gear it still won't go forward up a hill.
Oddball's problem is either in the twist stick or the rudder pedals - if your rudder is out of calibration your tank won't go past first gear or 5-10mph.
If your turret continues to move then you need to deadband your stick or add dampening.
I tanked for years with manual/automatic - Automatic is by far way easier to tank then Manual, for those that hate it simply haven't understood it.
People still use a joystick - I cant understand that part when tanking, a Mouse gives me the sensitivity to make easy 3-4k shots which a joystick can't do period.