Chevrolet 30 Series 1967 Service Manual page 410

CLUTCHES AND TRANSMISSIONS 7-24
The New Process four-speed heavy duty transmission
is a synchromesh type with helically cut gear teeth. The
transmission is bolted directly to the clutch and flywheel
housing at the rear of the engine.
cluster is a solid type with trunnion bearings mounted on
rollers in the case. There are four sets of gear teeth,
three helical and one spur (low gear) cut on this one-
piece forging. Gear teeth at front end are constantly
meshed with main drive gear and second and third speed
gear teeth are always meshed with mainshaft second and
third speed gears. The reverse idler gear is driven by
the countergear and mainshaft low and reverse sliding
(spur) gear engages teeth on countergear for first speed
operation or with reverse idler gear for reverse opera­
General maintenance of the transmission while mounted
in vehicle consists generally of lubrication at regular in­
tervals as described in LUBRICATION (Sec. 0) of this
supplement. In addition to lubrication, transmission
mounting bolts should be kept tight.
The transmission must be removed from truck for all
m ajor repair operations. Detailed instructions for re­
moval and installation of transmission is described later
in this section under "Transmission Replacement." Pro­
cedures for repair of the transmission are described
later in this section under "Transmission Overhaul."
REAR OIL SEAL REPLACEMENT
The lid type oil seal (24, fig. IN) at rear of transm is­
sion can be replaced without removing the transmission
from vehicle. Replace rear oil seal as described in the
following:
Removal
1. Remove drain plug and remove lubricant from
transmission.
2. Disconnect propeller shaft from transmission output
yoke as described in PROPELLER SHAFT (SEC. 4).
3. Remove propeller shaft brake parts (if used) from
transmission as described
(SEC. 5).
4. Remove speedometer driven gear from rear bearing
retainer.
5. Remove output yoke retaining nut. Pull output yoke
off mainshaft.
. Using a suitable puller, remove oil seal from rear
6
bearing retainer. Discard oil seal.
Installation
1. Using a suitable sleeve, install a new oil seal in rear
bearing retainer with lip of seal pointing in. Prelube
between lips of seal. Drive seal into bore of retainer
flush with rear face. Sealing cement should be used
at outer diameter of seal to prevent leakage. Wipe
off excess cement.
2. Install output yoke on mainshaft and into bearing re­
tainer. Install retaining nut. Tighten nut securely.
3. Install propeller shaft brake parts (if used) as de­
scribed in "HAND BRAKE" (SEC. 5).
4. Connect propeller shaft to output yoke as described
in PROPELLER SHAFT (SEC. 4).
5. Install speedometer driven gear and connect speed­
GENERAL DESCRIPTION
The countergear
MAINTENANCE AND ADJUSTMENTS
in "HAND BRAKE"
tion. The main drive gear is supported by a ball bearing
assembly at the front of the transmission case. The front
of transmission mainshaft is supported by bearing rollers
located in a cavity in rear of transmission main drive
gear and a ball bearing assembly supports the mainshaft
at rear of the transmission case.
shaft is fitted with a universal joint yoke, end of which
locates in an oil seal in end of the rear bearing cap. The
conventional transmission shift lever is attached by
means of a bayonet lock and can be installed directly into
transmission cover from the outside without removing the
cover from transmission. Optional remote controls are
the two rod type.
ometer drive cable.
. Install drain plug in transmission case and refill
6
transmission with lubricant as described in LUBRI­
CATION (SEC. 0).
REMOTE CONTROL ASSEMBLY
NOTE: If transmission is equipped with re­
mote controls and if the assembly requires re­
pairs or overhaul, proceed as follows:
Removal
1. With transmission in "Neutral," disconnect control
rods from shift levers at transmission.
2. Remove remote control bell crank retaining snap
ring.
3. Remove four bolts and lock washers attaching re­
mote control assembly to transmission cover.
4. Remove remote control assembly and gasket.
card gasket.
5. Overhaul remote control assembly as described later
in this section under "Transmission Overhaul."
Installation
1. Position remote control assembly and new gasket on
transmission cover.
2. Install four attaching bolts and lock washers. Tighten
bolts firmly.
3. Install remote control bell crank retaining snap ring.
4. Connect control rods to shift levers at transmission.
Adjustment
1. Remove cotter pins and clevis pins attaching control
rods at adjustable clevis end of rods.
2. Position gearshift lever at control island panel per­
pendicular (90°) to island panel and secure in this
position.
3. Place selector lever and shift lever at transmission
in neutral position.
4. Adjust clevises on control rods as required to obtain
free entry of clevis pins. Install pins.
5. Check adjustment by shifting transmission into all
positions and check for free entry of clevis pin in
each position. After obtaining correct adjustment,
secure clevis pins with new cotter pins and tighten
locknuts against adjustable clevises.
. Lubricate linkage as directed in Lubrication Sec­
6
tion .
0
Rear end of the main­
Dis­
CHEVROLET TRUCK SERVICE MANUAL