I have an '04 crew cab short bed GMC 2500hd 2wd lifted 6" front with 3" blocks in the rear W/ 325/65/18 tires. I'm getting a very noticable shudder in the drivetrain when starting out from a dead stop that goes away once the truck is moving. It's worse when towing and starting out uphill. I put a set of Fabtech traction bars on and it helped slightly. Then I made an 1 1/2" spacer block for the center carrier bearing on the drive shaft. That helped the most but there is still some shudder when starting. Could it be transmission or that the carrier bearing was damaged from driving it this way for awhile? I purchase the truck lifted this way. Does it need a one piece driveshaft or am I the only one who has this problem?