Jacks lock down when reversing, lift up when driving forward
This Renault Magnum has an XL motor for the drive and an M-motor for the steering. When the steering blocks, the coupling changes between locked, where you can latch a trailer onto it and unlocked, which releases the trailer.
I have tried to recreate as many details as possible in this scale (1:25) while maintaining the functionality with a working differential and the dual functionality of the M-motor. The doors open to reveal the interior with seats, steering wheel and center console.
The trailer locks the jacks when it is pushed backward, as seen in the video.