Case 621E Wheel Loader Service Manual

Table of Contents

• General
• Engine
• Fuel System
• Electrical System
• Steering
• Power Train
• Brakes
• Hydraulic
• Mounted Equipment
• Electrical Schematics
• Hydraulic Schematics

Manual Extract: TRANSMISSION OPERATION

The transmission is equipped with a Transmission ECM (Electronic Control Module). This module controls modulation and shifting that were normally associated with hydraulically modulated transmissions, providing smoother shifts and enhanced clutch life.

The Transmission ECM relies on signals from several sensors that are incorporated into the design. These sensors measure the speed of several components, as well as other sensors that measure temperature.
These solenoids and sensors are further defined in the following paragraphs.
In addition, the transmission incorporates a two-piece transmission case for ease of transmission maintenance, helical cut gears that help reduce noise, and all external hoses have been eliminated (all oil passages are internal).

Transmission ECM
Modulation and shifting are controlled by the Transmission Electronic Control Module (Transmission ECM). This module replaces the oil and springs that are found in hydraulically modulated transmissions.
The Transmission ECM controls the clutch engagement, providing smoother shifts and enhanced clutch life, whether the transmission is set to the automatic or manual shift mode.
The Transmission ECM also informs the Information Center, by the use of diagnostic codes, of any transmission error and the hours of operation that the error occurred.