Allison Transmission Fluid and Filter Change

122SD mm 26.04.01

When draining transmission fluid, check for evidence of dirt or water contamination. A small amount of condensation will appear in the fluid during operation.

Water contamination is normally characterized as a milky discoloration of the transmission fluid. Obvious contamination of the transmission fluid indicates a leak between the water and fluid areas of the transmission cooler. Inspect and pressure-test the cooler to confirm the leak; replace leaking transmission coolers.

  1. If the transmission fluid is not at normal operating temperature, run the engine until the fluid reaches operating temperature: 160 to 200°F (71 to 93°C).
  2. Park the vehicle on a level surface, apply the parking brakes, and chock the tires.
  3. Clean the area around the drain plug and the transmission fluid pan. Place a drain pan under the transmission and remove the drain plug. Examine the fluid as it drains.
  4. Remove the 12 mounting bolts (six each) from the two filter covers.

    5. Note:  A considerable amount of fluid will drain when the filter covers are removed.

  5. Remove the filter covers, O-rings, and two square-cut seals from the transmission. See Fig..

    1. Filter Cover

    2. Filter Element

    3. Filter Element O-Ring

    4. Square-Cut Seal

    5. Gasket

    6. Capscrew

    7. Drain Plug

    Fig. 1, Allison Transmission Filter Location and Components

  6. Remove the filters from the bottom of the control module.
  7. Lubricate the new O-rings with transmission fluid, then install them on the cover assemblies.
  8. Install a new square-cut seal on each cover assembly, then install the fluid filter elements on the cover assemblies.
  9. Install the filter and cover assemblies into the filter compartment.
  10. Align each cover assembly with the holes in the channel plate sump, and push the cover assemblies in by hand to seat the seals.

    11. Notice: Do not use the bolts to draw the filter covers to the sump. This can damage the covers, seals, or sump.

  11. Install six bolts in each cover, and torque the bolts 38 to 44 lbf·ft (51 to 61 N·m).
  12. Replace the drain plug O-ring, then install the drain plug. Tighten the drain plug 18 to 24 lbf·ft (25 to 32 N·m).
  13. Refill the transmission with fresh automatic transmission fluid and check the fluid level. See Table. for transmission lubricant capacities, and Table. for approved transmission lubricants.

    Table 1, Allison 4000 SeriesTransmission Lubricant Capacities

    Allison 4000 Series Transmission Lubricant Capacities1

    Sump Size

    Refill Capacity : qt (L)

    4 Inch

    39 (37)2

    2 Inch

    31 (30)†
    1. Quantities listed are approximate. Add listed amount of fluid, then perform a "hot check" and add fluid as needed. Do not overfill.
    2. Add 3 qt (2.8 L) for transmissions with PTO.

    Table 1, Allison 4000 SeriesTransmission Lubricant Capacities

    Table 2, Allison Approved Automatic Transmission Lubricants

    Allison Approved Automatic Transmission Lubricants

    Transmission

    Lubricant Type1

    Allison 4000 Series

    Castrol TranSynd (synthetic) or other Allison Approved TES 295 Fluid

    Allison Approved TES 389 Fluid or Dexron®-VI2 IMPORTANT: For TES 389 and Dexron-VI, use maintenance interval M1.
    1. Lubricants listed in order of preference. Do not mix fluid types. Call 1-800-252-5283, or see www.AllisonTransmission.com for a complete list of Allison approved lubricants.
    2. Dexron-VI may only be used in units beginning with S/N 6610220990.

    Table 2, Allison Approved Automatic Transmission Lubricants

Note:
Parent topic: Transmission
Document Number: 0000125536
Manual Publication Date: 2025-02-11
Topic Publication Date: 2024-06-21