AUTOMATIC TRANSMISSION NAG1 - SERVICE INFORMATION
DESCRIPTION
The NAG1 automatic transmission (Fig. 1) 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 vehi-
cle. 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 New-
ton 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 freewheel-
ing 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 vehicle and engines.
Basically, the automatic transmission with elec-
tronic control offers the following advantages:
• Reduces fuel consumption.
• Improved shift comfort.
• More favourable step-up through the five gears.
Fig. 1 NAG1 Automatic Transmission
1 - TORQUE CONVERTER 11 - PARKING LOCK GEAR
2 - OIL PUMP 12 - INTERMEDIATE SHAFT
3 - DRIVESHAFT 13 - FREEWHEEL F2
4 - MULTI-DISC HOLDING CLUTCH B1 14 - REAR PLANETARY GEAR SET
5 - DRIVING CLUTCH K1 15 - CENTER PLANETARY GEAR SET
6 - DRIVING CLUTCH K2 16 - ELECTROHYDRAULIC CONTROL UNIT
7 - MULTI-DISC HOLDING CLUTCH B3 17 - FRONT PLANETARY GEAR SET
8 - DRIVING CLUTCH K3 18 - FREEWHEEL F1
9 - MULTI-DISC HOLDING CLUTCH B2 19 - STATOR SHAFT
10 - OUTPUT SHAFT 20 - TORQUE CONVERTER LOCK-UP CLUTCH
VA AUTOMATIC TRANSMISSION NAG1 - SERVICE INFORMATION 21 - 3