9000 L4-1985cc 2.0L DOHC (1986)
Technical Service Bulletin # 07910126
Date: 910701
Speedometer - Gear Application
CATEGORY
Transmission
SECTION
PAGE
4
3
ISSUE
CODE
07/91-0126
473
Subject:
Transmission Speedometer Gears
Application:
9000 Models, M86-
Since the introduction of the Saab 9000, there have been two different types of gear sets used to provide a road-speed signal from the transmission to
other components in the car. The first type of gear set was applicable to cars up through the 1988 model year, while the second type is used on cars
M89-. In some instances, the second type gear set may be fitted on rebuilt transmissions for variants -M88 if updating of the differential housing was
required.
On 9000 models, the gear sets consist of a metal drive gear and a plastic driven gear. The drive gear is located on the right-hand side of the differential
housing and rotates at the same speed as the differential housing and wheels. Meshed with the drive gear is the plastic driven gear, which spins the shaft
for the electronic speed transducer fitted to the outside of the transmission. The speed transducer generates a signal to provide information on how fast
the car is travelling.
If an early-style drive gear is used in a gearbox together with a late-style driven gear, they will not mesh with each other and the speedometer will not
work. Conversely, it is not possible to mix a late-style drive gear with an early-style driven gear because they will not fit in the gearbox together.
Outlined below is further information on how to identify the early vs. late style gears and a method for diagnosing transmission-related speedometer
complaints should a rebuilt gearbox be installed and subsequently the speedometer not work.
Identification of Gears
Early Type, -M88