THEORY OF OPERATION - CONTINUED
TRANSMISSION - CONTINUED
Countershaft transmission is a power shift transmission that has four forward speeds and three reverse speeds.
Transmission has six clutches that are engaged hydraulically. Five clutches are disengaged by a coil spring. Clutch
6 is disengaged by wave spring and balance seal assembly. Balance seal assembly helps prevent clutch from drag-
ging if an engine overspeed condition occurs.
Balance seal assembly and wave spring are assembled inside clutch piston. When clutch 6 is not engaged, force
from wave spring and pressure from lube oil combine to move clutch piston to clutch disengaged position.
Transmission has five shafts: Input shaft assembly, output shaft assembly, and three gear shafts. Input shaft assem-
bly is driven by torque converter turbine. One gear shaft assembly contains clutch 1 (forward low) and clutch 2
(forward high). Another gear shaft assembly contains clutch 3 (reverse) and clutch 4 (second speed), and a third
gear shaft assembly contains clutch 5 (third speed and fourth speed) and clutch 6 (first speed).
Parking brake assembly is mounted to transmission case.
Each transmission gear shaft assembly's carry clutches has three internal oil passages. One passage carries oil for
lubrication and cooling of clutches, bearings, and gears. Two passages carry pressure oil for engagement of
clutches on each shaft.
In order to transfer power through transmission, both a speed clutch and a direction clutch must be engaged.
Torque converter inlet relief valve limits torque converter inlet oil pressure to protect torque converter.