By Eric Seifert
Automotive Technical Editor
Mark, an accomplished bowler, is known for “rattling” the pins with his monster strike ball. But lately, his 2001 Pontiac Grand Am has been rattling his nerves. Mark said the rattle comes from the transmission while parking at the bowling alley before his league begins. When he leaves, the noise is gone. I had seen this problem before on another customer’s Sunfire, and I advised Mark that all he needed was a little oil.
Some customers may comment on a grinding or rattle-type noise coming from the manual transmission. The noise usually occurs with the transmission in first or second gear at low RPM and can be intermittent. This condition may be from the natural harmonics of the engine that leads to a vibration in the transmission.
There are two separate noises. Follow these diagnostic procedures to determine which noise the vehicle has and perform the repair. If you compare like vehicles, they must have the same motor and similar mileage.
Three quarts of GM P/N 21018899 Saturn Manual Transmission Lubricant will be required to complete the Noise #1 repair procedure.
Diagnosis for Noise #1
This is a very distinct noise that is usually much louder than the second noise 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.
Diagnosis for Noise #2
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.
2000-02 Chevrolet Cavalier
2001-02 Oldsmobile Alero
2000-02 Pontiac Sunfire
2001-02 Pontiac Grand Am with manual transmission (RPO M86 or M94)
(Review lifting and jacking safety procedures in the ALLDATA system before beginning.)
Repair for Noise #1
Replace the transmission fluid with Saturn Manual Transmission Lubricant, P/N 21018899. Overfill to a capacity of 2.4 L (2.6 qts). A possible side effect of this repair may be a higher shift effort.
1. Raise and support the vehicle.
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 and tighten to 38 N.m (28 lb ft).
5. Lower the vehicle.
6. Remove the fill plug/cap 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 procedure.
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 and tighten the fill plug/cap.
Repair for Noise #2
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.
Written by ALLDATA Technical Editor, Eric Seifert. Eric is an ASE certified Master Technician and Engine Machinist. He is a graduate of the De Anza College Automotive Technology Program, with 20 years of independent shop and parts store experience.
For additional information, visit www.alldata.com.