Detroit™

cen mm 35.01.000

Notice: Failure to change the axle lubricant at more frequent intervals, when adverse operating conditions require, could result in axle damage.

Note: Axle lubricant change intervals are extended to 500,000 miles (800 000 km) on vehicles equipped with a Meritor RT40–145P or RT46–160P rear axle.

Important: On Detroit axles, the oil change interval for long haul vehicles can be extended to 500,000 miles (800 000 km) for axles with weight ratings of 34,000 to 40,000 lb (15 000 to 18 000 kg) using synthetic lubricant if a lubricant analysis shows adequate quality. Oil must be changed at least every four years, and more often if the axle is exposed to high temperatures and steep grades.

  1. Park the vehicle on a level surface, shut down the engine, and set the parking brake. Chock the tires.
  2. Clean the fill plug and the area around it. In the axle housing rear cover, remove the plug from the oil fill hole. See Fig..

    • Front View

    • Rear View

    1. Axle Breather

    2. Breather Hose

    3. Temperature Sensor Port

    4. Oil Fill Plug

    Fig. 1, Detroit Tandem Axle (forward axle shown)

    3. Caution: Be careful when draining the axle oil. It may be very hot, and could cause personal injury if it contacts the skin.

  3. Place a drain pan under the rear axle drain plug. Drain the oil when it is warm. At this temperature, the oil will run more freely and ensure that the axle is flushed.
  4. Clean the fill and drain plugs. Change them if necessary.
    1. For magnetic plugs, use a piece of key stock or any other convenient steel slug to short the two magnetic poles and divert the magnetic field.
    2. Clean away the collected material deposited on each pole. Magnets will rapidly lose their effectiveness as collected material bridges the gap between the two poles.
    3. After the first oil is changed, inspect the drain plug each time for large quantities of metal particles.
    4. After cleaning, install the drain plug(s) and tighten to 30 lbf·ft (41 N·m).
  5. Fill the axle with the recommended lubricant. See Table. for recommended drive axle lubricants and Table. for lubricant capacities.

    Note: Some Detroit axles have a small tapped and plugged hole near and below the housing oil fill hole. This smaller hole is for a lubricant temperature indicator only, and should not be used as a fill or level hole.
      1. Fill the axle through the oil fill hole. Lubricant should be level with the bottom of the oil fill hole. To check fluid level, see Fig..
      2. Install and tighten the fill plug 30 lbf·ft (41 N·m).

        Table 2, Detroit Drive Axle Lubricants

        Detroit Drive Axle Lubricants 1

        Important: Lubricant used in Detroit rear axles must meet Mercedes-Benz specification 235.20 (mineral) or 235.8 (synthetic). Mobil Delvac™ Gear Oil A 80W-90 and Mobilube™ HD-A Plus 80W-90 meet specification 235.20. Mobil Delvac 1 Gear Oil 75W-90 and Mobilube 1 SHC 75W-90 meet specification 235.8.

        Type

        Ambient Temperature

        SAE Viscosity Grade

        Mineral Oil

        –15°F (–26.1°C) and up 2

        80W–90

        Synthetic Oil

        –40°F (–40°C) and up

        75W–90
        1. Detroit rear axles do not require the use of friction modifiers.
        2. There is no upper limit on the ambient temperature.

        Table 2, Detroit Drive Axle Lubricants

        Table 3, Detroit Rear Axle Lubricant Capacity

        Detroit Rear Axle Lubricant Capacity

        Axle

        Oil Capacity:

        Quarts (liters)

        Forward-Rear

        15.9 (15.0) 1

        Single and Rearmost Tandem

        10.6 (10.0)

        1. Actual oil capacity might vary slightly depending on gear ratio.

        Table 3, Detroit Rear Axle Lubricant Capacity

        • Correct (lube level at bottom of fill hole)

        • Incorrect (lube level below fill hole)

        Fig. 2, Axle Lubricant Level Inspection

    Note:
    Parent topic: Cleaning of the Axle Lubricant and Filter Change, and Magnetic Strainer
    Document Number: 0000122170
    Manual Publication Date: 2025-02-11
    Topic Publication Date: 2024-06-04