Spicer Single Drive Axles Service Manual: 34DS, 34RS, 38DS, 38RS, DS340, RS340, DS380, RS380, DS400, RS400, DS3 - Manual (Page 26)

Adjustments
23
Differential Carrier Adjustments
Adjustments help provide optimum axle life and performance by correctly positioning bearings and gears under load. The tandem
axles covered in this manual require the following adjustments:
Bearing Preload: This adjustment is performed for both pinion and differential bearings. It maintains proper gear alignments by
creating correct bearing cone and cup relationships for free rotation under load. The pinion pilot bearing does not require a preload
adjustment.
Ring Gear Tooth Contact: This adjustment positions ring gear and pinion for best contact under load. Correct adjustment distrib-
utes torque evenly over gear teeth and helps maximize gear set Iife.
Input Shaft End Play (Forward Axles): This adjustment controls gear mesh in the inter-axle differential. Proper adjustment helps
maximize life of all power divider parts.
Adjust Input Shaft End Play
Specifications: Input shaft end play requirements will vary with operating conditions, mileage and rebuild procedures. These vari-
ations are shown in the following chart.
Input Shaft End Play
New or Rebuild with new parts: 0.003" to 0.007".
Rebuild with reused parts: 0.013" to 0.017".
Note: Because of manufacturing variations in individual parts, correctly adjusted end play could vary 0.010", after the unit is ro-
tated.
Acceptable End Play Tolerances when measuring as a regular maintenance procedure with axle in truck.
Up to 0.060" with over 100,000 miles or 1 year service off-road.
Up to 0.040" with less than 100,000 miles or 1 year service on- road.
Note: If end play exceeds limits, disassemble power divider and replace worn parts.
Procedure - Measure and Adjust End Play
1.
In September 1988, a Spring and a Thrust Button between the input and output shafts. End play tolerances are the same
for axles with or without this Spring and Button. However, end play measurement procedure is different than described
below. Refer to Service Bulletin Supplement at back of this manual for procedure variances.
With power divider assembled to differential carrier, measure end play with dial indicator positioned at yoke end of input shaft.
Move input shaft axially and measure end play. If end play is not correct (see chart), adjust as follows.
2. Remove input shaft nut, flat washer and yoke. Remove bearing cover cap screws and lock washers. Remove cover and shim
pack.
3. To increase end play, add shims:
Desired end play: 0.003" to 0.007"
Measured endplay (Step 1): 0.001" - 0.001"
Add shims to provide desired end play : 0.002" to 0.006"
IMPORTANT