Information on Gear Ration Change for Automatic Transaxles used with SOHC. Saturn Saturn 1993

For 1990-2009 cars

# Information on Gear Ration Change for Automatic Transaxles used with SOHC

Subject: | Information On Gear Ratio Change for Automatic Transaxles (MP6) Used With SOHC (LKO) Engine

Models: | All 1993 Saturn SL1 Sedans, SW1 Station Wagons and SC1 Coupes equipped with MP6 automatic transaxles built after, and including VIN PZ156140.

### Purpose

To help reduce the number of parts required at the assembly plant, the first gear ratios will become common between both the MP6 and MP7 automatic transaxles.

Since vehicles with the new gear ratios require a different PCM calibration, always check the VIN breakpoint to make sure that the correct calibrations is downloaded, if you are replacing a PCM

### Parts Requirements

There are three ways of identifying which gear ratio is installed as a transaxle:

1. Check the vehicle identification number and compare against VIN breakpoints are referred to as 1st design and vehicles built after the VIN breakpoint are referred to as 2nd design.)
2. Change code stamped on converter housing has been changed from "0" to "1" when this change was implemented.

NOTE: Every model year the change code will start back at "0".

3. Proper gear can be identified by the number of teeth according to the following chart:

AUTOMATIC TRANSAXLE
Gear and Hub Assembly - 1st Drive | MP6 - 2nd Design | MP6 - 1st Design
Part Number | 21002588 | 210025441
Number of Teeth | 19 | 21
Gear - 1st Driven |  |
Part Number | 21002633 | 21002634
Number of Teeth | 48 | 47
Transaxle Assembly | 210022847 Base (MP6) | 21002462 Base (MP6)
PCM/TC EEPROM ID | 7386 | 8198 or 3294

NOTE: If a calibration download is required on a 1993 vehicle, refer to this bulletin to select the proper calibration from the service stall system (SSS), which is determined by the vehicle identification number (VIN).

Important: After the new calibration has been installed, vehicle must be driven until operating temperature is reached. This allows the PCM to relearn variations in the fuel system and transaxle electronic controls that improve driveabilty and engine idle.