Your lorry is stuck in snow. You use the diff-lock to move off. When should you switch the diff-lock off? Your lorry is stuck in snow. You use the diff-lock to move off. When should you switch the diff-lock off?

• Possible answers:

   
• A. Only after selecting top gear
• B. Once the engine has warmed up
• C. As soon as the vehicle is moving
• D. As soon as the snow has cleared