If Shudder Occurs After the TCC has Applied

As mentioned above, the TCC is not likely to slip after the TCC has been applied. Engine conditions may go unnoticed under light throttle and load, but they become noticeable after the TCC apply when going up a hill or accelerating. This is due to the mechanical coupling between the engine and the transmission.

Once the TCC is applied, there is no torque converter, fluid coupling, assistance. Engine or driveline vibrations could be unnoticeable before TCC engagement.

Inspect the following components in order to avoid misdiagnosis of TCC shudder. An inspection also avoids the unnecessary disassembly of a transmission or the unnecessary replacement of a torque converter.

• Spark plugs

  Inspect for cracks, high resistance or a broken insulator.

• Plug wires

  Look in each end. If there is red ozone dust or a black carbon substance present, the wires are bad. Also, inspect for a white discoloration of the wire. This indicates arcing during hard acceleration.

• Coil

  Inspect for black discoloration on the bottom of the coil. This indicates arcing while the engine is misfiring.

• Fuel injector

  The filter may be plugged.

• Vacuum leak

  The engine will not get the correct amount of fuel. The mixture may run rich or lean depending on where the leak occurs.

• Exhaust gas recirculation (EGR) valve

  The valve may let in too much or too little unburnable exhaust gas and could cause the engine to run rich or lean.

• Manifold absolute pressure (MAP) or mass air flow (MAF) sensor - possibly a vacuum leak

  The engine will not receive the correct amount of fuel for proper engine operation.

• Carbon on the intake valves

  Carbon restricts the proper flow of air/fuel mixture into the cylinders.

• Flat cam

  Valves do not open far enough to let the proper fuel/air mixture into the cylinders.

• Oxygen sensor

  This sensor may command the engine rich or lean for too long.

• Fuel pressure

  Fuel pressure may be too low.

• Engine mounts

  Vibration of the mounts can be multiplied by TCC engagement.

• Axle joints

  Inspect for vibration.

• Throttle position (TP) sensor

  The TCC apply and release depends on the TP sensor in many engines. If the TP sensor is out of specification, the TCC may remain applied during initial engine loading.

• Cylinder balance

  Malfunctioning piston rings or poorly sealed valves can cause low power in a cylinder.

• Fuel contamination

  Fuel contamination causes poor engine performance.