Loading Tractor onto Rollback

What happens here

The rollback tow truck arrives on site. The driver backs the truck into position near the tractor. The flatbed of the tow truck is lowered, and the tractor is carefully winched onto the bed. During this process, the previously locked rear wheel surprisingly unlocks itself due to the slippery, greasy surface of the rollback bed, allowing the tractor to roll more easily onto the truck.

Goal: Transport the tractor onto the tow truck's flatbed.