MD and HD Series

sd plus mm 26.07.002

Notice: To prevent dirt from entering the transmission, use only clean containers and fillers for the transmission fluid. Do not use fillers or containers that have been used for water or antifreeze. Dirt, water, or antifreeze could damage the transmission.

  1. Park the vehicle on a level surface, shut down the engine, and set the parking brake. Chock the tires.
  2. Operate the vehicle until the transmission reaches normal operating temperature: 160 to 200°F (71 to 93°C).
  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. If only the filter is being changed, do not drain the fluid.
  4. Remove the 12 mounting bolts (six each) from the two filter covers.

    5. Note: A lot 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

    Fig. 1, Allison MD and HD Series Transmission Filter Locations and Components

  6. Remove the filters from the bottom of the control module.
  7. Lubricate the new O-rings with transmission fluid, and install them on the cover assemblies.
  8. Install a new square-cut seal on each cover assembly, and 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. Install a new drain plug O-ring, and install the drain plug. Tighten the drain plug 18 to 24 lbf·ft (25 to 32 N·m).
  13. Refill the transmission with fresh Dexron® transmission fluid, shown in Table., and check the fluid level. See Table. for lubricant capacities.

    Table 1, Approved Allison Transmission Lubricants

    Approved Allison Transmission Lubricants

    Lubricant Type1

    Temperature: °F (°C)

     All Allison Transmissions 

    Castrol TranSynd™ (synthetic)

    Above –22 (–30)

    Dexron® III

    Above –13 (–25)
    1. Lubricants listed in order of preference. Do not mix types of oil.

    Table 1, Approved Allison Transmission Lubricants

    Table 2, Allison Transmission Lubricant Capacities

    Allison Transmission Lubricant Capacities

    Transmission Model

    Fill Capacity:1 qt (L)

     HD/MD Series 

    HD4060/4560 (standard sump)

    36 (34)2

    HD4060/4560 (shallow sump)

    26 (25)2

    MD3060/3066/3560 (standard sump)

    19 (18)

    MD3060/3066/3560 (shallow sump)

    10.5 (10)
    1. Quantities listed are approximate. Add the recommended amount of fluid as listed under fill capacity, then perform a "hot check" and add fluid as needed. Do not overfill.
    2. Add 3 quarts (3 liters) if equipped with a PTO.

    Table 2, Allison Transmission Lubricant Capacities

  14. Check and adjust the fluid level using the appropriate Allison Transmission procedure.
Note:
Parent topic: Allison Transmission Fluid and Filter Changing
Document Number: 0000121160
Manual Publication Date: 2024-06-03
Topic Publication Date: 2024-10-31