Transmission Components
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| Illustration 1 | g02574956 |
(1) Filter inlet pressure test port (scheduled oil sampling port) (2) Filter outlet pressure test port (3) Two M16x2 rear mounting and lifting points (4) Torque converter output speed sensor (5) Conventional ten bolt PTO at 1:00 o'clock position (6) No. 1 SAE J615 side mounting bolt pad spacing six M16x2 threads (7) Oil filler and dipstick location (8) Standard 120 mm (4.72 inch) deep sump oil pan (9) Four M16x2 threaded mounts (10) Transmission output speed sensor (11) Optional 1085 N·m (800 lb ft) rear PTO capability (12) Rear magnetic drain plug (1 1/16 - 12 - 2A O-ring face seal) (13) SAE J1926 #4 auxiliary PTO lube (14) Output yoke (15) Transmission mounted cartridge type oil filter | |
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| Illustration 2 | g02575236 |
(16) Input shaft from engine flywheel (17) Flex plate (18) Flywheel gear (19) Torque converter housing (20) Input speed sensor to planetary transmission from engine (21) Breather (22) Receptacle (23) Electronic control module (ECM) (24) Temperature sensor (pump outlet and filter inlet) (25) Modulating valve (26) Guard (ECPC valve guard) (27) Filter outlet pressure port (PTO lube port) (28) Conventional ten bolt PTO at 8 o'clock position (29) Oil flow from cooler (30) Lube oil pressure tap (31) Oil flow to cooler (32) Torque converter out pressure tap (33) Oil cooler inlet pressure tap (34) Temperature sensor to cooler (35) Torque converter outlet relief valve (36) Main hydraulic relief valve (37) Filter bypass valve | |
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| Illustration 3 | g02580124 |
(38) Retarders add 104 mm (4.09 inch) to the length of the CX31 Transmission. (39) Retarder activation solenoid (40) Retarder activation pressure port (41) SAE J1926 #24 inlet from cooler (42) SAE J1926 #24 outlet to cooler | |
Control of the transmission planetary is achieved by hydraulically actuated clutches that hold selected components of the planetary group stationary. This design allows drive through the transmission. Each combination of clutches produces a different gear ratio and speed.
Transmission Hydraulic System
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| Illustration 4 | g01266253 |
(45) Pressurized oil (46) Solenoid (ECPC modulating valve) (47) Modulating valve | |
Oil is supplied by the transmission pump through a filter. Oil (45) is available to each modulating valve (47) .
Control of the transmission planetary is achieved by hydraulically actuated clutches. These clutches hold selected components of the planetary group stationary in order to allow drive through the transmission.
Shifting of the transmission is controlled by the electronic control module (ECM). The ECM acts in response to various inputs.
Inputs to the ECM module include the following information.
- Selected Gear
- Engine Speed
- Output Speed
- High Gear Limit
The control of the transmission also accounts for factors such as the temperature of the transmission oil.
Shifting of the transmission gears involves the release of one clutch and the subsequent engagement of the next clutch.
Each clutch is engaged by hydraulic oil pressure that is supplied by the modulating valves. The modulating valves are controlled by pulse width modulated signals (PWM). The signals are sent by the ECM to individual solenoid (46) on each modulating valve (47) .
For details of the operation of the modulating valves, refer to Systems Operation, Testing and Adjusting, "Modulating Valves (Electronic Clutch Pressure Control)".
The pressure of the oil in the clutches is proportional to the electrical current that is supplied to solenoid (46) that controls the clutch.
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| Illustration 5 | g00766511 |
A high current input is made initially. This function overcomes the inertia of the valve and the clutch components and this function initiates filling of the clutch. The current is reduced as the clutch is filled with oil and the plates move toward engagement. The current is held at a minimum value in order to allow the pressure of the oil in the clutch to increase slowly. The clearances between the plates and the disks are taken up smoothly. This period is called touchup. Once the plates and the disks are in contact, the current is increased gradually. This function will ensure that maximum pressure is applied to the clutch in a smooth manner.
Electronic control of this process provides improved quality of transmission shifts.
A combination of clutches engages each of the six forward gears and reverse gear.
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| Illustration 6 | g02583139 |
(15) Oil filter (47) Modulating valve (48) Torque converter (49) Torque converter lockup clutch (50) Torque converter outlet relief valve (51) Oil to the transmission cooler (52) Relief valve | |
Drive to the planetary transmission is through torque converter (48). The torque converter allows the speeds of the engine and the transmission to be matched smoothly. Once the speed of the engine and the transmission is matched, torque converter lockup clutch (49) engages. This action allows direct drive between the engine and the transmission.
Oil is supplied to the torque converter by relief valve (52) .
Oil from the torque converter flows through torque converter outlet relief valve (50) to the transmission cooler. The torque converter outlet relief valve maintains a required pressure in the torque converter.
Transmission shifts are dictated by operating conditions. Transmission shifting is automatic. The appropriate gear ratio is selected for the speed of the engine and the transmission output speed. Operator inputs can alter the shifting of the transmission. Examples of operator inputs are the selection of a highest permissible gear or the selection of transmission hold. Features such as overspeed protection and the application of the engine compression brake can also alter the shifting of the transmission.