TM 5-3810-300-24 & P2
Regular Axle Service.
Refer to Field Maintenance Manual No. 1, "Lubrication", for recommended service interval. Service the inter-axle
differential housing at the same time and in the same manner as the axle housings. Completely drain the lubricant while
the unit is warm. Whenever the inter-axle differential housing has been drained, always add an additional 2 U.S. pints of
specified lubricant directly to the interaxle differential housing.
Some newer model axles have a small tapped and plugged hole located near and below the housing lubricant level hole.
This smaller hole has been provided for the use of a lubricant temperature indicator only and should not be used as a fill or
level hole.
Jack up all four wheels of the assembly and run at 25 M.P.H. in high transmission gear for five minutes to thoroughly
circulate the lubricant throughout the assembly. Be sure brakes are fully released.
TIRES.
Measure the rolling radii of all tires. The tires of all wheels must be matched to within 1/8" of the same rolling radius (3/4"
of the same rolling circumference). The four largest tires should not be installed on one driving axle and the four smallest
tires on the other driving axle of through drive type tandems. Such tire mounting will cause inter-axle "fight", unusually high
axle lubricant temperatures that result in premature lubricant breakdown and possible costly axle service.
In addition to matching individual tire rolling radii or rolling circumference, we recommend matching, as nearly as possible,
the total tire circumference of one driving axle to the total tire circumference of the other driving axle. This will usually
result in satisfactory tandem axle lubricant temperatures that lengthen drive unit service with higher tire mileage.
How To Match Tandem Tires.
The vehicle should be on a level floor, carrying a correctly distributed rated capacity load. Be sure all tires are the same
size. Measure new tires to be sure they will be correctly matched.
A.
Inflate all tires to the same pressure.
B.
Carefully measure the rolling circumference of each tire with a steel tape.
C.
Mark the size on each tire with chalk and arrange them in order of size, largest to smallest.
D.
Mount the two largest tires on one side of one axle and mount the two smallest on the opposite side of the same axle.
E.
Mount the four other tires on the other axle in the same manner.
F.
Test run the vehicle to get accurate rear axle lubricant temperature readings on the two axle lubricant temperature
gauges.
G.
Vary tire air pressure within the tire manufacturer's recommended range, so the lubricant temperatures of both axles
are within 30F of each other and not in excess of 220F. This will usually result in uniform tire loading and good tire
life.
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