INFO. ON GEAR RATIO CHANGES FOR AUTO TRANS USED W/SOHC ENG. Saturn Saturn 1993

For 1990-2009 cars

# INFO. ON GEAR RATIO CHANGES FOR AUTO TRANS USED W/SOHC ENG

#### SUBJECT: ------- Information On Gear Ratio Change For Automatic Transaxles (MP6) Used With SOHC (LKO) Engine

#### MODELS AFFECTED: -------- All 1993 Saturn SLl Sedans, SWl 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 calibration is downloaded, if you are replacing a PCM.

PARTS REQUIREMENTS: ------------ There are three ways of identifying which gear ratio is installed in a transaxle:

1. Check the vehicle identification number and compare against VIN breakpoints given under "MODELS AFFECTED." (Vehicles built before the VIN breakpoint are referred to as lst 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 "O".

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 21002541 Number of Teeth 19 21

Gear - lst Driven

Part Number 21002633 21002634 Number of Teeth 48 47 Transaxle Assembly 21002847 Base (MP6) 21002462 Base (MP6) PCM/RC 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 driveability and engine idle.

General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.