Need help with strapping down on snatch truck

[TechniKal]

So I got a 2011 Dodge 3500 snatch truck and I'm coming into a problem where ill use my d hook cloth strap and I'll strap it down on the claw and horizontal bar and when I'm going I hit a bump the claws move a bit and the strap loosen and comes off at points any ideas of what I can do. Like certain straps or add on

[BlackAutoload]

What type of wrecker unit do you have? 

[ESC]

My guess from the description would be an Eagle Claw.   I remember that same issue when I was first thrown into an Eagle Claw with no training.  If thats the case, here is a video that I found showing how to.