Sorry, not really up on the later gearboxes, the last vauxhall one I had in bits was an F10 twenty plus years ago! I can't think of anything you can do on an engine swap that would cause the problem. Is it definitely your box? Might also be worth checking the oil level, I have seen a box that wouldn't come out of gear because it had been stood and the selectors were 'dry'Mr drew im in need of your expertise!! I’ve had an engine swap done on my zafira gsi and after it was done my car now won’t select anything other than 3rd which it’s stuck in!! The gearbox was fine before although the lever in the car was sloppy it worked I’ve taken the cables off and can manually move it back and forth but the knuckle to go up/Down won’t budge,do you know if anything could get damage other than the selector
It’s only nuts and bolts,don’t be afraid!!