Dana Model 20 Transfer Case - Chevrolet 1973 Overhaul Manual

7 M - 5 0 CLUTCHES A ND M A N U A L T R A N S M IS S IO N S
Fig. 26Q—Installing Mainshaft Rear Bearing Lock Nut
(4-Wheel
Drive Only)

DANA MODEL 20 TRANSFER CASE

Disassembly.................................................. .................... 7M-50
Cleaning and Inspection.............................................. 7M-52
DISASSEMBLY
1. Remove cover from bottom of transfer case.
2. Remove poppet hole cap screws from the outside of
the front bearing retainer.
3. rJRemove the intermediate gear shaft lockplate at the
Jfe ^ re a r side of the transfer case.
f u s in g dummy shaft J-23419, drive intermediate
shaft out of rear of case as shown in Figure 2D.
'mitv Remove intermediate gear and thrust washers from
case.
3
6. Remove bolts attaching rear output shaft subassem­
bly to transfer case and remove complete unit from
case as shown in Figure 3D.
NOTE: Disassembly of rear output shaft sub-
assembly is covered later in this section.
7. Remove locknut and washer from front output
shaft yoke, if not removed during unit removal
from vehicle, and slide yoke from output shaft.
8. Loosen dog set screw from rear wheel drive shift
fork. Rotate shift rail to preload poppet ball and
pull rail out of the housing. Remove shift fork and
clutch gear from case. Remove poppet ball and
spring from retainer.
16. Move all transmission gears to neutral except the
reverse idler gear which should be engaged
approximately 3/8 of an inch (leading edge of
reverse idler gear taper lines.up with the front edge
of the 1st speed gear). Install cover assembly with
new gasket to transmission case. Shifting forks must
slide into their proper positions on clutch sleeves
and reverse idler gear. Forks must be positioned as
in removal.
17. Install cover attaching bolts and torque to 20-25 ft.
lbs.
18. Using Tool J-8109, replace gearshift lever and
check operation of transmission.
Index
Disassembly of Rear Output Shaft.......................... 7M-52
Assembly of Rear Output Shaft................................7M-53
Assembly............................................................................. 7M-54
9. Remove front output shaft rear cover and shims.
. Tie shims together before laying aside.
10. Tap on front end of front output shaft, removing
shaft from the rear of the case as shown in Figure
4D. Remove front washer, front bearing, gear
washer, and output gear from case as they clear
shaft. This procedure will also remove the rear
bearing cup.
NOTE: Remove front bearing cup as
required, using a suitable puller or driver.
11. Loosen dog set screw from the front wheel drive
shift fork. Swing fork and gear toward cover
opening and lift out gear. Rotate shift rail to
preload poppet ball and pull rail out of the retainer.
Remove fork as it clears the shift rail and remove
poppet ball and spring from retainer.
12. Support inner race of rear bearing and press
bearing from shaft as shown in Figure 5D.
13. Remove front output shaft bearing i*etainer and
14. Remove shift rail Up seals with a suitable puller or
pry tool.
15. Remove the front bearing retainer seal using a
suitable*duller or pry tool.
OVERHAUL MANUAL