2002 G500
When driving at 25 to 40 MPH the truck shakes centrally. During this time shifted from drive into neutral, appears no change (i.e. engine RPM reduced but driveline still running at same speeds). Checked engine mounts, transmission mounts, tcase mounts; appear ok.
Appears G500s have vibration issues. Appears the majority of these vibrations is due to the three driveshafts/propeller shafts; rear driveshaft, front driveshaft and central shaft from transmission to transfercase. All of these shafts have CV joints with the rear and front driveshafts having non-boot dual u-joint type CVs and the central shaft having booted ball bearing type CV joints.
Unbolted front driveshaft to isolate which driveshaft may be out of balance or bad CV joints resulting in vibrations. Here's the odd part being a numerous Jeep owner. Once the front driveshaft was removed the g500 would not go into any gear when moving the shifter. The shifter would move from park, reverse, neutral and drive but nothing would happen. On my Jeeps, if you remove the front driveshaft the jeep's rear driveshaft would still operate the drivetrain and move the vehicle. Then I engaged the central locker and felt power restored to the drivetrain; and putting the truck in reverse and drive worked! Anyone know why you have to lock the central differential to get the truck to move without the front driveshaft installed? With ALL TIME 4 wheel drive... the truck should transfer power to the rear driveshaft to move the vehicle.