Chevrolet 1977 10 Series, Руководство по ремонту, Страница: 97 / 468

REAR AXLE DIFFERENTIAL
4B-25
o r 10-15 inch pounds on reused b earin g s. Use an
inch-pound torque w rench such as J-5853, as shown
in figure 28B, to m easure the ro ta tin g torque.
N O T E : A fter torque has been checked, final
tig h ten in g should be d one very cautiously.
F o r exam ple, if w hen checking, torque was
fo u n d to be 5 in c h -p o u n d s, a d d itio n a l
tig h ten in g o f the p in io n n u t as little as 1/8
tu rn can add 5 ad d itio n al inch p o u n d s drag.
T h erefo re, the p in io n n u t should be fu rth e r
tightened only a little at a tim e an d torque
should be checked a fte r each slight am o u n t
o f tig h ten in g . Exceeding torque specifications
m ay com press the collapsible spacer too fa r
and req u ire its replacem ent.
10. R otate the pinion several tim es to assure th a t
b earings have been seated. C heck p relo ad ag ain . If
d ra g has been re d u c e d , re -se t p re lo a d to
specifications.
CHECKS AND ADJUSTMENTS
F o u r adjustm ents are essential fo r p ro p e r o p e ra tio n o f
the differential and its related p arts. These ad ju stm en ts
are a) P inion B earing P reload, b) Side B earing P reload,
c) Pinion D e p th and d) R ing G e a r-to -P in io n Backlash.
Pinion B earing Preload is set to specifications in step 8
o f "D riv e P in io n -In stallatio n a n d A d ju stm en t".
Side B earing Preload is set to specifications in step 9 o f
" D ifferen tial C ase-Installation an d A d ju stm en t".
Follow ing service to the D ifferen tial Case or to the D rive
P inion and R ing G ear, a G e a r T ooth C ontact P a tte rn
Check
must
be m ade to v erify the accuracy o f the w ork
in setting the p in io n d ep th a n d the rin g g e ar-to -p in io n
backlash.
Gear Tooth Contact Pattern Check
P rior to final assem bly o f the differen tial, a G e a r T ooth
Fig. 28B—Measuring Rotating Torque
C ontact P attern Check is necessary to v e rify the correct
relatio n sh ip betw een rin g g ear a n d drive p in io n . G e a r
sets w hich are not p o sitio n ed p ro p e rly m ay be noisy, or
have short life, or both. W ith a p a tte rn check, the m ost
desireable contact betw een rin g g e a r and drive p in io n
for low noise level an d long life can be assured.
GEAR TOOTH NOMENCLATURE
The side o f the rin g g e a r tooth w hich curves outw ard, or
is convex, is re fe rre d to as the “ d riv e ” side. T he concave
side is the “ co a st” side. T he en d o f the tooth n earest
center o f ring g ear is re fe rred to as the “ to e ” end. The
end o f the tooth fa rth e st aw ay fro m cen ter is the “ h eel”
end. Toe end o f tooth is sm alle r th a n heel end. See
Figure 29B.
Test
1. W ipe oil out o f c a rrie r an d carefu lly clean each
tooth o f rin g gear.
2. Use g e ar m a rk in g co m p o u n d and apply this
m ixture sp arin g ly to all rin g , g e a r teeth using a
m edium stiff brush. W h en p ro p e rly used, the area
o f p in io n tooth contact will be visible w h en h an d
load is applied.
3. T ighten b e a rin g cap bolts to 55 lb. ft.
4. E xpand b rake shoes until a to rq u e o f 20-30 lb. ft. is
required to tu rn the pin io n .
N O TE: A test m ade w ith o u t lo ad in g the
gears will not give a sa tisfac to ry p a tte rn .
T urn co m p an io n flange w ith w rench so th at
ring g ear ro tates one full rev o lu tio n then
reverse ro tatio n so th a t rin g g e a r ro tate s one
revolution in opposite d irectio n . Excessive
tu rn in g o f rin g g e a r is not reco m m en d ed .
5. O bserve p a tte rn on rin g g e a r teeth an d com pare
w ith F igure 30B.
Fig. 29B—Gear Tooth Nomenclature