Pilot Bearing

Failing Pilot Bearing, Bushing on Manual Transmissions

Most rear wheel drive, and some front wheel drive, vehicles with manual transmissions use a pilot bearing/bushing. The pilot bearing/bushing

Most rear wheel drive, and some front wheel drive, vehicles with manual transmissions use a pilot bearing/bushing. The pilot bearing/bushing ­supports and centers the transmission input shaft and clutch disc. When the clutch is disengaged, the pilot bearing/bushing allows the flywheel to ­maintain engine RPM while the input shaft is ­slowing down and stopping.
Types of pilot bearing/bushing include conventional ball bearings, needle bearings and sintered bronze bushings.
When a pilot bearing/bushing fails, a vehicle may exhibit: 
• No release;
• The transmission may pop out of gear;
• Noise;
• Vibration; and
• Catastrophic failure of the transmission if not fixed

Fig. 2

Early signs of the pilot failing may be noise whenever the clutch is disengaged. The driver may also notice that the transmission is difficult to shift between gears or hard to put into reverse or first gear when stopped.
When the pilot is failing, or has failed, the input shaft will be allowed to walk around causing it to go off center. When this happens, the transmission input shaft will begin moving around inside the transmission causing the gears and synchronizers to be off center resulting in the transmission popping out of gear.
If the vehicle has a high output engine, the misalignment will cause the input shaft gear to not mesh with the counter shaft gear properly and ultimately will cause the gears to fail.  (see figures 1 and 2).
When a clutch is replaced, the pilot bearing/bushing should always be replaced as part of the service.

You May Also Like

New Oil Specifications

Many 0W16 oils have a new donut certification mark on the bottle called API SN-PLUS and SN-PLUS Resource Conserving.

You may have noticed that some Toyota and Honda four-cylinder vehicles require SAE viscosity 0W16 oil. You may also have noticed it in the catalog pages or on the shelves of your oil supplier. The oil really stands out – the last number is strange because it does not end in a five or a zero. 

Solving Intermittent Overheating

New cooling systems anticipate and influence changes in coolant temperature.

Ignition Systems

The ignition coil is a very simple and robust circuit.

Alternator Testing For No Charge Conditions

Many alternator problems turn out to be nothing more than a bad connection at the alternator or a bad wiring harness.

Lifter Deactivation

The area of contact between the lifters and cam lobes is the highest loaded surface inside an engine.

Other Posts

Battery Charging and Diagnostics

Here are six tips to use when diagnosing a vehicle with a dead battery. 

Diagnosing Crankshaft Position Sensors

Modern engines need to not only know the position of the crankshaft, but the position of the camshafts.

Electronic Throttle Body Service

On most systems, idle speed is completely controlled by the throttle plate angle.

Spark Plug Evolution

Spark plugs have changed over the years.