Description & Operation: Introduction
Automatic transaxle is an electronically controlled transaxle with 4 forward speeds and one reverse speed. Transaxle consists of clutches, mainshaft, countershaft, secondary shaft, shift control solenoid valves, clutch pressure control solenoid valves and lock-up torque converter. See Fig 1 .
Valve body assemblies consists of main valve body, regulator valve body, servo body and accumulator body. Transaxle shifting and torque converter lock-up are controlled by the Powertrain Control Module (PCM). PCM receives information from various inputs and uses this information to control solenoid valves for proper transaxle operation.
Gearshift lever has 6 positions. When gearshift lever is moved, manual valve on main valve body is moved by the shift cable. Gearshift lever also changes position of the transmission range switch, mounted near gearshift lever. Transmission range switch delivers an input signal to PCM to indicate gearshift lever position. PCM uses input signal, and operates shift control solenoid valves to control transaxle shifting.
When certain transaxle gear combinations are engaged by clutches, power is transmitted from mainshaft to countershaft via secondary shaft to final drive gear, providing different gears.
Torque converter lock-up engages and transaxle mainshaft rotates at same speed as engine crankshaft when transaxle is in "D" position (2nd, 3rd and 4th gears), or "D" position with overdrive mode off (3rd gear). Under certain conditions, torque converter lock-up clutch is applied during deceleration when in 3rd and 4th gears. PCM receives various input signals and operates clutch pressure control solenoid valves. Operating clutch pressure control solenoid valves controls modulator pressure.
PCM contains a self-diagnostic system, which will store a Diagnostic Trouble Code (DTC) if a failure or problem exists in the transaxle electronic control system. DTC can be retrieved to identify transaxle problem area.
Overdrive (O/D) switch is located on end of gearshift lever. When ignition switch is turned to ON position, overdrive is turned on. When overdrive switch is depressed, overdrive is turned off. O/D OFF indicator light, located next to "D" position indicator on instrument panel, will illuminate. When overdrive is off, transaxle selects only 1st, 2nd and 3rd gears. When overdrive is on, transaxle uses all 4 forward gears.
Transaxle is equipped with shift and key interlock systems. Shift interlock system prevents gearshift lever from being moved from "P" position unless brake pedal is depressed and accelerator is in idle position. In case of a malfunction, gearshift lever can be released by placing ignition key in release slot near gearshift lever. Key interlock system prevents ignition key from being removed from ignition switch unless gearshift lever is in "P" position. For additional information on shift and key interlock systems, see SHIFT INTERLOCK SYSTEMS - CR-V article.
The A/T gear position indicator on instrument panel contains lights to indicate which position transmission range switch on gearshift lever is in.