Grinding/Rattle Type Noise Coming From Transmission (Diagnose and Perform Repair)

Some customers may comment on a grinding or rattle type noise coming from the transmission. The noise usually occurs with the transmission in first or second gear at low RPMs and can be intermittent.

This condition may be originated by the natural harmonics of the engine that leads to a vibration in the transmission.

There are two separate noises. Follow the diagnostic procedures listed below to determine which noise the vehicle has and perform the outlined repair. If you are comparing like vehicles, you must compare vehicles with the same motor and similar mileage.

This is a very distinct noise that is usually much louder than the second noise that can be associated with this transmission. If the vehicle is not making any noise when trying to verify the condition, it can be induced by making several tight left hand circles with the vehicle at normal operating temperature. Making a sharp right hand turn will usually stop the noise. While the noise is occurring, in order to distinguish between the two noises, you can press lightly on the clutch pedal without releasing the clutch and the noise will NOT go away or change. As a second diagnostic aid, while the vehicle is making the noise, shift to third gear and the noise will stop. If the noise is determined to be this type, perform the repair for noise #1.

Replace the transmission fluid with Saturn Manual Transmission Lubricant, P/N 21018899. Overfill to a capacity of 2.4L (2.6 qts). A possible side effect of this repair may be a higher shift effort.

1. Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle in the General Information sub-section of the appropriate Service Manual.
2. Place a suitable container under the transmission assembly.
3. Remove the drain plug located on the bottom of the transmission and completely drain the fluid.
4. Re-install the drain plug.

Tighten
Tighten the drain plug to 38N·m (28 lb ft).

5. Lower the vehicle.
6. Remove the fill plug located on the top/middle of transmission on the driver side, near the red vent cap. If you use the check level plug on the side of the transmission, you will not be able to overfill the transmission.

Important: Fill the transmission to the amount specified. Too much lubricant will cause the fluid to leak from the vent. Not enough fluid will defeat the purpose of this bulletin.

7. Fill the transmission with 2.4L (2.6 qts) of Saturn Manual Transmission Lubricant P/N 21018899. DO NOT USE THE RED VENT CAP TO FILL.
8. Re-install the fill plug.

Tighten
Tighten the fill plug to 38 N·m(28 lb ft).

This noise, commonly referred to as gear rattle, can be induced by lugging the engine in any gear, but is usually most noticeable in first or second gear. While the noise is occurring, if you press lightly on the clutch pedal without releasing the clutch, the noise will be reduced or eliminated.

Do not attempt to repair this noise. This is a characteristic of the vehicle and any vehicle equipped with a manual transmission can be made to make a similar noise. Driving at slightly higher engine RPM levels will reduce this noise.

Parts are currently available from GMSPO.

For vehicles repaired under warranty, use: