Vibration in my son's 2003 Mustang

I recently had the clutch replaced in my son’s 2003 Mustang and when I got it back it had a vibration in 5th gear at 60mph and in almost every gear when you let off the gas and decelerate while it is still ingaged. It levels off an then as the car starts to slow down because of the engine and I get a vibration that feels as if is coming from underneath the car. I had them turn the drive shaft 180 degrees but no change. As an example, in 3rd gear while decelerating with the clutch engaged the vibration comes in about 40mph. If you disengage the clutch all vibration ceases. No one can give me any suggestions. HELP!!!

Did they replace the pliot bearing? I think the whole job needs to be taken back apart and inspected.

One possibility could be a worn U-joint although one would hope that this would have been checked carefully while the driveshaft was out. It’s often assumed that a tight U-joint is a good one and that is not the case. Special attention should be paid to the front joint.

Some clutch assemblies are balanced as a unit and marked. Maybe the pressure plate is out of whack with the flywheel. I would think that if this were the case any vibration should be apparent while revving the engine in neutral with the clutch pedal depressed.

That’s in addtion to the pilot bearing comment and if the U-joints are fine then I tend to agree that this thing probably needs to come back apart.

Did the flywheel get resurfaced or replaced?