Meritor
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.
Single drive axles equipped with traction equalizers may require a "limited-slip friction modifier" to correct a slip-stick condition, as described in the vehicle driver's manual. Meritor's experience shows that the following additives (friction modifiers) perform adequately:
-
For all synthetic gear oils other than Mobil, add 1.6 ounces (35 mL) of additive for each pint (0.5 L) of lube capacity:
-
Elco No. 2 Friction Modifier (Elco Corporation).
-
Lubrizol No. 6178 (Lubrizol Corporation).
-
Hi-Tec E-336 (Edwin Cooper, Inc.).
-
Equa-Torque No. 2411 (Sta-Lube Corporation).
-
Equa-Torque No. 2414 (Sta-Lube Corporation).
-
-
For Mobilube SHC (synthetic) use Mobil No. 204 (Mobil Oil Corporation). Add 1.1 ounces (23 mL) of additive for each pint (0.5 L) of lube capacity.
Important: These friction modifiers generally deteriorate faster than conventional extreme-pressure additives, so the lubricant change schedule must be shortened when using these additives. The traction equalizer additive (and recommended drive axle lubricant) must be changed at the Maintenance 2 (M2) interval, instead of the Maintenance 3 (M3) interval recommended in the Maintenance Operation Chart for axles that require only those lubricants recommended in Table..
- Park the vehicle on level ground, apply the parking brakes, and chock the tires.
- Remove the axle carrier fill plug (see Fig. ), then remove the drain plug from the bottom of the housing and
completely drain the lubricant while the unit is warm. Allow sufficient
time for all old lubricant to drain. On dual drive axles, it is also
necessary to remove the plug at the bottom of the interaxle differential
housing to drain the lubricant.
Table 1, Meritor Drive Axle Recommended Lubricant
Meritor Drive Axle Recommended Lubricant
Lubricant Type
Ambient Temperature
Lubricant SAE Viscosity Grade
Meritor Specification
Synthetic Gear Oil
–40°F (–40°C) and up 1
75W–90
0–76–N
–40°F (–40°C) and up
75W–140
0–76–M
- There is no upper limit on these outside temperatures.
Table 1, Meritor Drive Axle Recommended Lubricant
- If so equipped, replace the axle oil filter. Remove the
oil filter, using a suitable filter strap wrench. See Fig.. Discard the filter.
Fig. 1, Axle Oil Filter Removal
- Using the specified drive axle lubricant, coat the face of the gasket on a new oil filter. Install the filter over the adapter, and tighten the filter one full turn after the gasket contacts the base; do not overtighten the filter.
- For a new or reconditioned axle, flush the axle with clean flushing oil, then drain it thoroughly. It is necessary to flush the axle the first time (only) that the axle lubricant is changed.
- Clean the fill and drain plugs. For magnetic plugs, a piece of key stock or any other convenient steel slug may be used to short the two magnetic poles and divert the magnetic field.
- After cleaning the drain plug(s), install and tighten to 35 lbf·ft (47 N·m).
- With the vehicle on a level surface, fill the axle housings
to the bottom of the fill hole, using specified lubricant. See Table. for recommended
axle lubricants, and Table. for drive
axle lubricant capacities.
Table 2, Meritor Drive Axle Lubricant Capacities
Meritor Drive Axle Lubricant Capacities
Axle Model
Capacity 1: pints (liters)
Single-Drive, Single Reduction 2
RS–21–160
39.5 (18.7)
RS–23–160
39.5 (18.7)
RS–23–161
37.2 (17.6)
RS–23–185
47.3 (22.4)
RS–25–160
37.2 (17.6)
Tandem-Drive, Single Reduction
RT–40–145, RT–40–145A, RT–40–145P
Forward
30.2 (14.3)
Rear
25.8 (12.2)
RT–44–145, RT–44–145P
Forward
29.3 (13.9)
Rear
25.1 (11.9)
RT–46–160, RT–46–160P
Forward
39.1 (18.5)
Rear
34.4 (16.3)
- Quantities listed are approximate. Fill axle until lubricant is level with bottom of fill hole with vehicle on level ground.
- See "Traction Equalizer Additives" in the text.
Table 2, Meritor Drive Axle Lubricant Capacities
- Install and tighten the fill plug 35 lbf·ft (47 N·m).
- Whenever the interaxle differential housing has been drained, add an additional 2 pints (1 L) of specified lubricant directly into the interaxle differential housing.
- For a two-speed axle with a shift unit, change the shift unit lubricant; see elsewhere in this maintenance operation for the shift unit lubricant changing procedure.
- Remove the chocks, then drive the vehicle, unloaded, for 1 or 2 miles (2 or 3 km) at speeds not to exceed 25 mph (40 km/h), to thoroughly circulate lubricant throughout the carrier and housing assemblies.
Note: There may be about one pint (0.5 L) of lubricant remaining in the filter. Be careful not to spill it when removing the filter.
Important: Axles should not be flushed with any solvent, such as kerosene.
Note: Meritor recommends plugs with elements having a minimum pickup capacity of 1-1/2 pounds (0.7 kg) of low-carbon steel, in plate or bar form. Magnets will rapidly lose effectiveness as collected material bridges the gap between the two poles. Clean or change the plugs before this occurs. It may be necessary to clean or change the plugs one or more times between lubrication change intervals.
Note: Some Meritor axles have a small tapped and plugged hole near and below the housing lubricant fill hole. This smaller hole is for a lubricant temperature indicator only, and should not be used as a fill or level hole.