Chevrolet 70 1969 Series, Руководство по ремонту

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REAR AXLE TWO-SPEED
REAR AXLE 4-17
(E A T O N 17201, 17221, 18201, 18221, 19201, A N D 19221)
This publication contains overhaul inform ation applica­
ble to Eaton 2-Speed R ear Axles. Refer to respective axle
“ Specifications” at end of this m anual for new limits, tol­
erances, torque readings, available spacer and adjusting
shim thicknesses, and other im portant overhaul inform a­
tion.
GENERAL DESCRIPTION
The 2-speed axle is a modification of the single reduc­
tion axle. A set of planetary gears and a sliding clutch
gear, installed between drive gear and differential, perm its
ratio change from low to high or vice versa (fig. I).
General construction of rear axle differential, pinion,
and planetary assembly is typically illustrated in Figure 2.
An electric power shifting arrangem ent is used in m a k ­
ing ratio changes. Refer to the Service portion of this
M anual for m aintenance inform ation.
Relative positions of differential assembly, bevel gear,
clutch plate, support case and differential are shown in il­
lustrations following in this publication.
HOUSING
The axle housing is one-piece design with spring seats
and housing cover welded in place. Brake shoe backing
plate is attached to a flange welded near outer ends of
housing. O uter ends of housing are m achined to acco m ­
m odate wheel bearings and threads are cut at extrem e
outer ends for installation of wheel bearing nuts.
AXLE SHAFTS
Full floating axle shafts are attached to hubs with
studs. Stud holes in shaft flanges are tapered and tapered
dowels are installed on each stud. Inner end of axle shaft
is attached to differential side gear by splines.
DIFFERENTIAL CARRIER
Differential carrier is attached to axle housing by cap
screws or studs and nuts, and m ay be removed w'ith co m ­
plete differential and planetary assemblies, after axle
shafts have been removed.
DRIVE PINION
Drive pinion is straddle m ounted between two opposed
tapered roller bearings at outer end and a straight roller
bearing at inner end. C om ponents of this assembly are il­
lustrated in Figure 14.
Tapered roller bearings are adjusted by selecting a spa­
cer of correct thickness to provide proper bearing adjust­
ment. Shim pack thickness, used between pinion cage and
carrier, can be varied to provide proper pinion and bevel
gear backlash, also gear tooth contact.
BEVEL GEAR AND SUPPORT CASE
Bevel gear is bolted between the two halves of gear sup­
port case. In addition to bevel gear teeth which mesh with
pinion teeth, teeth are also cut in inner diam eter of bevel
gear. These teeth mesh with teeth on idler pinions.
Two-piece support case encloses planetary m echanism
and differential case, and is supported at each end by ta­
pered roller bearings. C om ponents of this assem bly are il­
lustrated in Figure 17.
DIFFERENTIAL ASSEMBLY
Four pinion type differential is carrier in two-piece
case, with thrust washers m ounted between pinions and
case, also between side gears and case. Pins, installed in
left half side of case, act as shafts for idler pinions. Outer
ends of pins are supported by high speed clutch plate
H IG H R A T IO LO W R A T IO TP 5 0 64
F igu re 1— G e a r Positions in H ig h a n d Low R atios
CHEVROLET SERIES 70-80 H EAVY DUTY TRUCK SH O P M A N U A L