This manual covers the ELECTROMATIC JR403-E, an electronically controlled automatic transmission used in various light to medium-duty vehicles from GMC, Isuzu, Nissan, Mazda, and Mitsubishi, including the GMC Tiltmaster, from 1988 onwards. The JR403-E is a robust transmission, sharing design principles with the well-regarded Nissan RE4R01A, and is engineered for durability and smooth power delivery in demanding applications. It is designed to handle moderate to high torque outputs and features electronic control for optimized shift points and torque converter lock-up, contributing to efficiency and drivability.

This comprehensive workshop and service manual provides detailed information for the maintenance, diagnosis, and repair of the JR403-E automatic transmission. It covers essential areas including disassembly and reassembly, component replacement, hydraulic system testing, electrical component diagnosis, and routine maintenance procedures such as fluid and filter changes. The manual is intended for professional technicians and experienced DIYers, offering the necessary technical specifications, diagnostic charts, and repair procedures to ensure the proper functioning and longevity of the transmission.