Description - GMC 1989 Light Duty Truck Repair Manual

Figure 40— Measuring Backlash
$
Tighten
The bearing cap bolts (19) to 115 N-m (85 ft.
lbs.).
CHECKING BACKLASH
1. Mount a dial indicator with a magnetic base to the
axle housing as shown in figure 40.
2. Place the indicator tip at the heel end of the tooth.
3. Check the backlash at three equally spaced points.
T he b a c k la s h s h o u ld
(0.005-0.009-inch). The measurement must not vary
more than 0.05 mm (0.002-inch) between the points
checked.
4. High backlash is corrected by moving the ring gear
closer to the pinion.
5. Low backlash is corrected by moving the ring gear
away from the pinion.

DESCRIPTION

T he D ana 101 /2-inch ring gear rear axle uses a
conventional ring and pinion gear set to transm it the
driving force of the engine to the rear wheels. The gear
set transfers this driving force at a 90 degree angle from
the propeller shaft to the drive shafts.
This axle is full-floating. The axle shaft is supported at
the wheel ends by the wheel hubs. The bolts that attach
the shaft to the hub, support the axle at the hub. The
splined end of the shaft is supported by the differential.
The pinion gear is supported by two tapered roller
bearings. The pinion depth is set by a shim pack between
the inner pinion bearing cup and the rear axle housing.
The pinion bearing preload is set by a shim pack at the
front of the axle housing between the yoke and the pinion
gear.
The ring gear is bolted onto the differential case with
right-hand thread bolts.
be 0 .1 3 -0 .2 3 mm
10V2-INCH RING GEAR
tapered roller bearings. The differential and ring gear are
side bearing preload is set by the differential shim packs.
the rear axle housing.
different rates of speed while the rear axle continues to
transm it the driving force. This prevents tire scuffing when
going around corners and prevents premature wear on
internal axle parts.
and a gasket between the differential cover and the rear
axle housing.
the B or U Model, and the Heavy Duty Model.
DANA REAR AXLES 4B5-13
Figure 41— Installing the Axle Cover
6. To adjust the backlash, the differential case must be
removed from the housing, then the differential
bearings removed, and the proper number of shims
moved from one side to the other.
FINAL ASSEMBLY
-►*- Install or C onnect
1. Drive axles. Refer to the proper service manual.
2. RTV to the axle cover.
3. Axle cover (14) to the housing (figure 41).
$
T ighten
• The cover bolts (17) to 47 N-m (35 ft. lbs.).
4. Axle housing to the vehicle. Refer to the proper
service manual.
5. Lubricant to the rear axle (after the RTV has cured).
The differential case is supported in the case by two
located in relationship to the pinion by using selective
shims between the bearings and the differential case. To
move the ring gear, shims are deleted from one side and
an equal amount are added to the other side. Differential
Two bearing caps are used to hold the differential into
The differential is used to allow the wheels to turn at
The rear axle is sealed with a pinion seal, a hub seal,
Two models of the Dana 101 /2-inch are covered here:
F-04755