GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 1999 🢒 Chevy C Pickup - 2WD 🢒 Transmission/Transaxle 🢒 Automatic Transmission - 4L80-E 🢒 Reverse Servo Replacement

Removal Procedure
  1. Remove the transmission oil pan and filter. Refer to Automatic Transmission Fluid and Filter Replacement .

    2. Object Number: 512992 Size: SH
  2. Remove the rear servo assembly from the transmission case as follows:
    3. • Cover bolts (6).
    • Cover (5).
    • Cover gasket (4).
    • Bottom retaining clip (3).
    • Servo piston (2).
    • Outer ring oil seal (1).
    • Inner ring oil seal (7).
    • Accumulator piston (8).
    • Piston seal (9).
    • Washer (10).
    • Servo spring (11).
    • Servo spring retainer (12).
    • Selective pin (13).
    • Accumulator spring (14).

Checking Procedure

Tools Required

    • J 21370-10 Gage Pin
    • J 38737 Band Apply Pin Checking Tool

    Object Number: 102596 Size: SH
  1. Place the J 21370-10 in the servo bore.

    2. Object Number: 102591 Size: SH
  2. Position the J 38737 over the bore with the hex nut facing the parking pawl linkage.

    3. Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

  3. Fasten the J 38737 with the two rear servo cover bolts.

    4. Tighten
    Tighten the bolts to 24 N·m (18 Ib ft).

  4. Ensure the J 21370-10 moves freely in the tool and the pin bore.
  5. In order to determine the correct pin length, tighten the nut on the gauge.

    6. Tighten
    Tighten the nut to 34 N·m (25 Ib ft).


    Object Number: 413975 Size: LH
  6. Select the correct band apply pin length.

Installation Procedure

    Object Number: 512992 Size: SH
  1. Remove the rear servo assembly from the transmission case as follows:
    2. • Accumulator spring (14).
    • Selective pin (13).
    • Servo spring retainer (12).
    • Servo spring (11).
    • Washer (10).
    • Piston seal (9).
    • Accumulator piston (8).
    • Inner ring oil seal (7).
    • Outer ring oil seal (1).
    • Servo piston (2).
    • Bottom retaining clip (3).
    • Cover gasket (4).
    • Cover (5).
    • Cover Bolt (6).

    Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

  2. Install the cover bolts (61).

    3. Tighten
    Tighten the bolts to 24 N·m (18 lb ft).

  3. Install the transmission oil pan and filter. Refer to Automatic Transmission Fluid and Filter Replacement .