Systems Operation 784C, 785C and 785C HAA Off-Highway Truck/Tractors Power Train

Systems Operation 784C, 785C and 785C HAA Off-Highway Truck/Tractors Power Train

Transmission Planetary

SMCS - 3030; 3064; 3155; 3160; 3169; 3190

Power from the engine goes to the torque converter. The power then goes through the drive shaft to the transfer gears. The transfer gears are fastened directly to the front of the transmission case. The power then goes through the transmission to the differential.

The transmission has six forward speeds and one reverse speed. REVERSE and NEUTRAL use only torque converter drive. At lower ground speeds, FIRST speed uses torque converter drive. At higher ground speeds, FIRST speed uses direct drive. As the ground speed increases in FIRST speed, the lockup clutch of the torque converter engages. This provides FIRST speed with direct drive. The speeds SECOND through SIXTH use direct drive. There is a short period of torque converter drive between the direct drive speeds. This occurs while the clutches engage in the transmission. After the clutches are engaged, the torque converter lockup clutch automatically engages. The torque converter is in direct drive. Torque converter drive during the shifts provides smooth, automatic shifting.

The transmission has a combination of three rotating clutches, three stationary clutches, and four planetary units. This provides six forward speeds and one reverse speed. No. 1 clutch (5), No. 2 clutch (6), and No. 3 clutch (9) are the rotating clutches.

Input torque goes from the transfer gears to input shaft (1). Input shaft (1) drives the rotating housing and the transmission input clutch arrangement. No. 1 clutch (5) and No. 2 clutch (6) are part of the transmission input clutch arrangement. The remainder of the clutches are in the output section of the transmission. Center shaft (7) connects the input section to the output section. Center shaft (7) also carries the sun gears that drive the output section of the transmission. Center shaft (7) and input shaft (1) turn the same direction.

Power Flow in NEUTRAL-1