Clutch troubleshooting

Most drivers can expect a clutch to last 40,000 to 60,000 miles. Maintained well, it can last much longer, depending on the truck and how it is driven.

Keep the pedal adjusted

Most newer trucks with manual transmissions have self adjusting clutches that need no adjustment. On an older manual adjust clutch, keeping the pedal properly adjusted is the cheapest way to cut wear on the clutch disc.

If there is no free pedal play, the release (throw out) bearing can stay in contact and keep spinning even though the disc still engages. A bearing that turns constantly wears out, and the clutch then gets hard to shift into or out of gear.

Common symptoms and what they usually mean

• Slipping: engine revs climb but the truck does not pull. Often a worn disc, no free play, an oil soaked disc from a leaking rear main or input seal, or a weak pressure plate.
• Dragging or will not release: grinding going into gear from a stop. Often too much free play, a worn clutch brake, a warped disc or intermediate plate, or a failing hydraulic release.
• Grabbing or chatter: jerky engagement. Often contaminated facings, a glazed or cracked flywheel, or worn engine or transmission mounts.
• Noise with the pedal down: usually the release bearing. Noise with the pedal up can point at the input shaft bearing or the pilot bearing.
• Hard pedal: worn cross shaft bushings, a dry release bearing or a binding linkage.

Check before you call

• Is the pedal free play within spec for your clutch?
• When was the release bearing last greased? Many heavy duty clutches call for about every 50,000 miles in linehaul work.
• Any oil on the bell housing or dripping from the inspection cover?
• On a hydraulic release, is the fluid level right and the fluid clean?

If the clutch is slipping, do not keep driving it. The heat glazes the flywheel and pressure plate, and a disc job turns into a flywheel job. Call the shop and we will get the truck in.