my girlfriend has a 2001 quad cam 1500 when she backs up it makes a popin noise kinda faint but can hear it well also last night she was going about 35 mph and the whole truck shook she said it felt like she blew a tire but all good please help Cliff

Sounds like a universal joint siezing up,have the drive shaft removed and rotate each joint,probably find one sticking........or maybe some play in it.......