Series 2 vp no movement in overdrive

[centy]

My ex just scored herself a vp commodore lpg x cop car and in overdrive it does not move. In drive it runs fine.
When she got it the oil was very low, as i think the previous own was a bit of a tool ( blue neons under it).
I just need to know what to check to try and get it running correctly.
As a bonus i change the diff for her and a get a lsd for nix, but it needs the pinion bearing replaced.

PS if anyone has scanned pages relating to the box and diff it would be great help till i can get a manual.

[GoldCoastCommodoreSpares]

After topping up the transmission and resetting the kickdown cable, if the problem still exist's its most likely a clutch issue inside the box.