In the Motor Magazine April 2007 edition, a service alert mentions that some Nissan Sentra models with the 1.8L engine and the RE4F03B automatic transaxles may experience a chirping noise during the 2nd to 3rd up shifts. Nissan states that the chirping noise is most obvious during light acceleration (about 1/8 of the throttle or less) and it is due by internal problems in the high clutch assembly.

ATP Part No. AT-203 Friction Modifier can be added to the transaxle to cure this noise. Utilizing ATP Part No. AT-203 will get the similar desired results that are found in the Nissan transmission additive.  

Use the following steps below when adding the AT-203 Friction Modifier to the transaxle:

1. Start the engine and allow the transmission to get to normal operating temperatures.
2. Check the transmission fluid level before adding AT-203 Friction Modifier.
3. If the fluid level reads “HOT” on the dipstick, drain about 13.5 ounces of transmission fluid to compensate for the full bottle of AT-203 Friction Modifier. (DO NOT OVERFILL THE TRANSMISSION)
4. Check transmission fluid level and test drive vehicle.