Hy first I'm sorry for my bad English, I was French and I'm not very good to rot in English

I buy a Ranger 06 next week, but after a few miles I was thinking something is loose in the drive-train

When I push on the gas pedal and release it its like if it was some loose in it. It take like few millisecond too decrease speed and I feel a small bang .

I make a movie of the drive-train I can't explain better than this

Thank you for your help

http://youtu.be/J2JBPwYXyEQ