IDENTIFICATION
The LA4A-EL automatic transmission is identified by identification tag located on rear of transaxle and bottom of main control assembly. (Scheme 138)
Scheme 138
Note. For LA4A-EL transaxle electronic testing and repair, see the AUTO TRANS DIAGNOSIS - LA4A-EL article.
DESCRIPTION & OPERATION
The LA4A-EL is a 4-speed transaxle assembly. The LA4A-EL is controlled by both electronic and mechanical systems utilizing a compound planetary gearset, chain drive, final drive planetary gearset and an open differential. One band, 5 friction clutches, and 2 one-way clutches provide four forward gear ratios and reverse. (Scheme 139)
Input signals from sensors are sent to the Powertrain Control Module (PCM). The PCM can determine when the time and conditions are right for a shift or converter clutch application. The PCM can also determine line pressure needed to optimize shift feel.
Five electronic solenoids accomplish these functions; 2 On/Off solenoids for shifting, one Pulse-Width Modulator solenoid for torque converter clutch control, a Electronic Pressure Control (EPC) solenoid for line pressure control, and a 3-2 timing/coast clutch solenoid to control the release of the coast clutch and the coordinated release of the direct clutch and apply of the low and intermediate band. The PCM has built-in self-diagnosis, fail-safe code and warning code display for the main input sensors and solenoid valves.
Scheme 139
Stiff Shift Lever Operation
Check shift interlock system, shift linkage and manual valve (valve body).