why wont my gearbox engage after dropping new engine in

[Stokezi]

hi l having trouble getting my gear box to engage after we dropped a new engine in
auto gu 3
can anybody help
l have checked installed correctly .checked oil
can anybody help
cheers shane

[Stokezi]

l need running before l need a blue slip

[GQ TANK]

Do you have a manual box or auto box?

[Parksy]

Auto I think?

Have you checked fluid in transmission? You bolted the torque converter to the flex plate?

[GQ TANK]

Did the flexi plate bolt up. I read some where of some forgetting to remove a sapcer when the done a motr swap.