EQUIPMENT CHARACTERISTICS, CAPABILITIES AND FEATURES

TM 9--2520--215--34 0002 00--1 EQUIPMENT DESCRIPTION AND DATA 0002 00 THIS WORK PACKAGE COVERS: Equipment Description and Data EQUIPMENT CHARACTERISTICS, CAPABILITIES AND FEATURES The XT--1410--4 and XT--1410--5A transmission is the X--type. This means that the drive is delivered to left and right outputs. The transmission includes a torque converter with automatic lockup clutch, three forward-- and one reverse -- range gear and clutch groups, a cross shaft and bevel drive gears, two steer clutches and planetary gear sets, steer drive gearing and two output reduction gear assemblies with brakes. Three forward speeds and one re- verse speed are selected manually. HYDRAULIC SYSTEM The hydraulic system, because of its importance to the operation of the transmission, should be studied care- fully and understood. There are eight hydraulic system schematic illustrations, which show the various oil circuits and positions of valves and other moving components WP 0005 00. These schematic diagrams parallel the torque path schematic views WP 0005 00 The hydraulic schematic views illustrate what happens hydraulically. While the torque schematic diagrams illustrate what happens mechanically. The complete hydraulic system is shown on WP 0005 00. Torque Converter and Lockup Drive. Drive from the vehicle engine to the transmission range gearing is either hydraulic (torque converter) or mechanical (lockup) clutch engaged). Lockup drive is obtainable only when transmis- sion is operating in intermediate and high range. OIL LEVELS The hydraulic system is designed so that after the vehicle has been operated for a short time, two distinct oil levels are established in the transmission. One oil level is in the output gear compartment and is comparatively low WP 0005 00. The other is in the transmission sump. The purpose of having two oil levels is to provide sufficient vol- ume of oil in reserve while maintaining the most efficient level of oil in the operating section of the transmission. Two levels exist because air, as well as oil, is constantly being delivered to the output gear compartment of the transmission. This creates a constant air pressure which acts upon the oil in the output gear compartment. The air comes from two sources; from the scavenge pump which pumps a mixture of oil and air from the converter hous- ing, and from the brake coolant pump which pumps air during periods when the brakes are released. The air accumu- lates above the oil in the gear compartment and forces the oil level down and through a passage in a wall separating the gear compartment from the oil sump. When the oil reaches its proper level, excess air escapes into the sump and returns to the scavenge pump. DIFFERENCES BETWEEN MODELS--XT--1410--5A TRANSMISSION The XT--1410--5A Transmission was design to accommodate the conversion of the M88A1 vehicle to in- creased engine power (redesignated M88A2). The transmission is an adaptation of the XT--1410--4. Design changes resulted in a transmission entirely compatible with the M88A2 engine’s output characteristics. STEERING. The steer cross shaft durability is improved by hardening the snap ring grooves and the steering fric- tion plates design has changed from a sunburst pattern to a spiral pattern. The steer clutch pressure has also been changed by replacing the two springs in the steer valves with one spring. REVERSE AND LOW CARRIERS. The Reverse carrier spindles have been improved by adding a grooved pin to prevent movement. To prevent movement of the low carrier, a shoulder has been added to the head of the spindle. TORQUE CONVERTER. The torque converter vane angle has been changed to accept the increased horsepow- er output of the engine.