Hi I have a 98 Legnum VR-4 Auto and sometimes when i start it and put it into gear in jolts in to gear quite hard and will go into 2nd not 1st, even if I try to manually shift it will stay in 2nd. It will go away once i start driving but I have to accelerate hard upto about 70Km/h then it will change gear and be completely fine.

Also sometimes the transmission will slip when changing up gears but only sometimes and mostly only when going into 3rd but sometimes it will slip them all.

Transmission was rebuilt buy the previous owner and had the pressure turned up apparently.

Transmission has no codes even when its stuck in 2nd, however the engine has showed code 64 every time this has happened. (64 FR Alternator System Terminal)

Any help would be much appreciated.