Mercedes Benz repair manual

Mercedes Benz repair manual B150-B200

 AUTOMATIC TRANSMISSION NAG1 (WA580  W5A580)

The NAG1 automatic transmission is an electronically controlled 5-speed transmission with a lock-up clutch in the torque converter. The ratios for the gear stages are obtained by 3 planetary gear sets. Fifth gear is designed as an overdrive with a high-speed ratio.


NAG1 identifies a family of transmissions and means “N”ew “A”utomatic “G”earbox, generation 1. Various marketing names are associated with the NAG1 family of transmissions, depending on the transmisson variation being used in
a specific vehicle. Some examples of the marketing names are: W5A300, W5A380, and W5A580. The marketing name can be interpreted as follows:

W = A transmission using a hydraulic torque converter.
5 = 5 forward gears.
A = Automatic Transmission.
580 = Maximum input torque capacity in Newton meters.

The gears are actuated electronically/hydraulically. The gears are shifted by means of an appropriate combination of three multi-disc holding clutches, three multi-disc driving clutches, and two freewheeling clutches. Electronic transmission control enables precise adaptation of pressures to the respective operating conditions and to the engine output during the shift phase which results in a significant improvement in shift quality. Furthermore, it offers the advantage of a flexible adaptation to various vehicles and engines. Basically, the automatic transmission with electronic control offers the following advantages:

Reduces fuel consumption.
Improved shift comfort.
More favorable step-up through the five gears.
Increased service life and reliability.
Lower maintenance costs.