GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2008 🢒 TopKick C-Series (Conventional) C4/C5 🢒 Transmission/Transaxle 🢒 Manual Transmission - Medium Duty 🢒 Transmission Oil Changing

Removal Procedure

    Object Number: 790953 Size: SH
  1. Raise and suitably support the vehicle. Refer to Lifting and Jacking the Vehicle .
  2. Position a suitable container under the oil drain plug in order to catch the transmission fluid.
  3. Clean the area around the drain and fill plugs.
  4. If equipped with a Eaton® Fuller® FS series transmission, remove the oil fill plug (1).
  5. Remove the oil drain plug (2).

    6. Object Number: 790957 Size: SH
  6. If equipped with a Eaton® Fuller® RT series transmission, remove the oil fill plug (2).
  7. Remove the oil drain plug (1).
  8. If equipped with a Spicer® ES series transmission, remove the oil fill plug.
  9. Remove the oil drain plug.

Installation Procedure

    Object Number: 790930 Size: SH
  1. Ensure that the fluid is completely drained.
  2. Wipe the clean area around the drain plug.

    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. Install the oil drain plug.

    4. Tighten

    1. Tighten the Eaton® Fuller® transmission oil drain plug to 61 N·m (45 lb ft).
    2. Tighten the Spicer® transmission oil drain plug to 45 N·m (33 lb ft).
  4. Remove the drain pan.
  5. Fill the transmission to the correct level, using the correct type fluid, refer to Lubrication Specifications .
  6. If equipped with a Spicer® ES series transmission, install the oil fill plug.

    7. Tighten
    Tighten the Spicer® ES series transmission oil fill plug to 45 N·m (33 lb ft).


    Object Number: 790957 Size: SH
  7. If equipped with a Eaton® Fuller® RT series transmission, install the oil fill plug (2).

    8. Tighten
    Tighten the Eaton® Fuller® transmission oil fill plug to 82 N·m (60 lb ft).


    Object Number: 790953 Size: SH
  8. If equipped with a Eaton® Fuller® FS series transmission, install the oil fill plug (1).

    9. Tighten
    Tighten the Eaton® Fuller® transmission oil fill plug to 82 N·m (60 lb ft).

  9. Lower the vehicle.