Truck Repair: Engine/Clutch Rattle, clutch pressure plate, clutch pedal


Question
HI, Cliff - I have a 99 Century with a Cummins N-14Plus. My problem is that when the RPM's reach approx. 1400 and higher there is a loud rattling noise. I can apply a little pressure to the clutch pedal and the noise goes away, but I can feel a slight shaking in the pedal. Also each time I get a PM at Speedco w/1 Gallon of Lucas Oil added and the noise decreases drastically for about 1000 miles. Any idea's ?

Answer
Vibrations will travel through the driveline.You will have to start to eliminate the problems.If it does it sitting still,that will rule out rear ends,driveshafts,& U joints.If it just does it sitting still,tha will leave the vibration dampner,clutch,pressure plate,& flywheel.