Problem Reports

If the slip yoke in the driveshaft is binding, it can make a clunking noise when pulling away from a stop. The slip yoke will need to be lubricated.

This concern relates to vehicles equipped with the E4OD and 4R100 automatic transmissions. Fluid leaks from the rear of the transmission and excessive vibration felt in the vehicle while driving can be caused by a lack of lubrication to the rear of the transmission and rear seal failure. The extension housing (rear portion of transmission) can lose lubrication if the fluid supply hole becomes clogged. This leads to rear seal failure from lack of lubrication, and can cause bearing failure in the extension housing. The extension housing and gasket should be replaced and verify the fluid supply hole is clear of debris.

Electrolysis can cause repeated failures of the heater core and radiator. The diagnosing technician should check for voltage present in the coolant, with the battery disconnected, because electrical current in the coolant causes electrolysis. Corroded or deteriorated parts should be replaced, and the coolant should be flushed. Ground straps can be added to help prevent future corrosion of components.

Broken pieces from catalytic converter can travel to the muffler and rattle, causing a buzzing noise to be heard in the muffler or exhaust system. The exhaust catalytic converter and muffler/pipe assemblies should be replaced.

This concern relates specifically to the E4OD and 4R100 automatic transmissions. Transmission fluid leaking from the front of the transmission bell housing may also be accompanied with shifting and transmission engagement issues. This is often caused by transmission overheating and is the sign of a significant internal transmission problem. The superficial cause is the failure of the front pump seal of the transmission. The immediate repair is to remove the transmission, replace the front pump and seal, replace all fluid with the transmission filter, and verify proper flow through the transmission fluid lines and cooler. It is also recommended to make sure the vehicle is not pulling a load that is heavier than the gross vehicle weight limits because this can cause the transmission to overheat. Depending on the transmission's mileage, this can also be a good time to consider a complete overhaul or replacement with a remanufactured unit, as often just the pump and seal replacement is a short lived remedy.

The Check Engine Light may illuminate, the engine may run rough and have misfires on acceleration. Commonly the ignition coils and/or the ignition coil boots are the cause of this problem. The rubber boot that insulates the coil to the spark plug can dry and crack allowing arcing. Inspect the coils and boots, and replace them as needed. Our technicians also recommend replacing the coil boots any time the spark plugs are replaced.

A casting issue with the cylinder heads may allow fuel leakage into the cooling system. The cylinder heads should be inspected for fuel leakage where the injectors mount. Replacement of the cylinder head(s) that leak will be needed.