I went to Pats with a front driveline vibration after installing a 4 inch lift on my truck. They said after road testing and taking driveline measurements that my front driveshaft was operating at a extreme angle and a custom shaft needed to be made to fix the vibration. I knew a 4 inch lift should not run a too harsh of angles but got them to build a custom front shaft as per their recommendation. I paid nearly triple for the custom drive shaft and my truck was not fixed as they said it was.