Many noises believed to be coming from the transmission may be originating from other sources such as tires, road surfaces, wheel bearings, the engine or the exhaust system. These noises may vary according to vehicle size, type, and amount of body insulation used. A thorough and careful check should be made to determine the source of the noise before disassembling the transmission. The transmission gears, like any other mechanical device, are not absolutely quiet and will exhibit some normal operating noise. The following is a suggested approach to verify the suspected transmission noises.

1. Select a smooth, level asphalt road to reduce tire noise.
2. Drive the vehicle until the coolant has reached normal operating temperature.
3. Record the speed and the gear range at which noise, if any, occurs.
4. Check for noises with the engine running and the vehicle stopped.
5. Determine in which of the following drive conditions the noise is occurring:

•	Drive-light acceleration or heavy pull.

•	Float-maintaining constant vehicle speed at light throttle with the transmission in gear.

•	Coast-partially or fully closed throttle with the transmission in gear.

•	All of the above.

6. After road testing the vehicle, refer to DTC P0132 HO2S Circuit High Voltage Sensor 1 in Engine Controls - 1.6L, Noisy in Neutral with Engine Running , Noisy in First Gear Only , Noisy in Second Gear Only , Noisy in Third Gear Only , Noisy in Fourth Gear Only , Noisy in Fifth Gear Only , Noisy in Reverse Only , Slips out of Gear , Hard Shifting Effort .