Detailed Information on the M32 Gearbox

Background information on the M32 gearbox

The M32-6 is a 6-speed manual transmission. This transmission is being used for the first time in the Astra-H in conjunction with the Z 20 LEL DOHC II turbocharged petrol engine. This manual transmission is an all-synchromesh 3-shaft transmission.
This 3-shaft transmission has the following advantages:

Compact construction
Improved smooth-running performance
Better shift quality
High torque transmission
Low weight

Structure of the manual transmission
Location of the shafts
The following cross-sectional diagram shows the location of the respective shafts in the M32-6 transmission, as per the 3-shaft principle.

Upper main shaft
Input shaft
Lower main shaft
Differential gear

In this transmission angular cone bearings are used for all shafts. These bearings require a certain amount of play and pretension. The required amount of bearing play and pretension is achieved at the production stage by using shims under the angular cone bearing in the transmission housing.
Location of gearwheels
This diagram shows the location of the gearwheels on the respective shaft.

Lower main shaft
Input shaft with 1st/2nd gearUpper main shaft

1st gear gearwheel
2nd gear gearwheel
5th gear gearwheel
6th gear gearwheel
3rd/5th gear gearwheel
6th gear gearwheel
4th gear gearwheel
4th gear gearwheel
Reverse gear gearwheel
3rd gear gearwheel

One particular advantage of this 3-shaft transmission is that on the input shaft, the 3rd gear gearwheel is also used for 5th gear.
Power flow in the individual gears
The following diagrams show the flow of power in the individual gears.

1st Gear

2nd Gear

3rd Gear

4th Gear

5th Gear

6th Gear

Reverse

Location of components in the M32-6 transmission
The following exploded diagram shows the location of the components in the M32-6 manual transmission. The components of the individual shafts will then be described.

Axle shaft seal ring
Guide sleeve – differential housing
Differential housing
Seal ring – axle shaft seal ring sealing flange
Axle shaft seal ring sealing flange
Axle shaft seal ring
Shim
Differential assembly
Transmission housing
Upper main shaft assembly
Input shaft assembly
Lower main shaft assembly
Clutch bleed connector
Fastening sleeve
Reversing light switch
Central release
Pressure line
Clutch housing
Gearshift assembly
Magnet
Oil baffle plate

Location of components in upper main shaft assembly

Fluid collector pipe
Upper main shaft
Roller bearing – upper main shaft
Retaining ring
Needle roller bearing – reverse gear
Reverse gear gearwheel (driven)
Reverse gear shift sleeve
Synchro ring – reverse gear
Thrust piece
Synchroniser body
Spacer
Retaining ring
3rd gear gearwheel (driven)
Needle roller bearing – 3rd gear gearwheel
Intermediate ring
Synchro ring
3rd/4th gear shift sleeve
Thrust piece
Synchroniser body
Retaining ring
Shim
Roller bearing – main shaft
Needle roller bearing – 4th gear gearwheel
4th gear gearwheel
Intermediate ring
Synchro ring
3rd/4th gear shift fork
Gear shift shaft
Reverse gear shift fork

Location of components – lower main shaft assembly

Thrust piece
Retaining ring
1st/2nd gear shift sleeve
Outer synchro ring
Intermediate ring
Inner synchro ring
2nd gear gearwheel (driven)
Needle roller bearing – 2nd gear gearwheel
Locking ring
Pressure piece
5th gear gearwheel (driven)
Needle roller bearing – 2nd gear gearwheel
Synchro ring
Thrust piece
Synchroniser body
Retaining ring
5th/6th gear shift sleeve
Synchro ring
6th gear gearwheel (driven)
Needle roller bearing – 6th gear
Roller bearing – main shaft
Shim
5th/6th gear shift fork
Gear shift shaft
1st/2nd gear shift fork
Synchroniser body
Outer synchro ring
Intermediate ring
Inner synchro ring
1st gear gearwheel (driven)
Needle roller bearing – 1st gear gearwheel
Retaining ring
Roller bearing – main shaft
Main shaft
Fluid collector pipe

Location of components – input shaft assembly

Input shaft seal ring
Roller bearing
Input shaft
1st gear gearwheel (driving)
2nd gear gearwheel (driving)
Input shaft bolt
Shim
Input shaft bearing
6th gear gearwheel (driving)
4th gear gearwheel (driving)
Spacer
3rd/5th gear gearwheel (driving)

Synchronisation
An improved synchronisation system, already fitted to the F40 manual transmission, is used on the M32-6 transmission. The previous sliding blocks and synchro springs have been dispensed with and have been replaced with thrust pieces.
Matched synchronisation systems are also used for the individual gears.
Two and three-cone synchronisation systems are used.
The synchronisation systems used for each respective gear will be shown in the following.
1st/2nd gear
The three-cone synchronisation system is used for these two gears.

Inner synchro ring
Intermediate ring
Outer synchro ring
Shift sleeve
Synchroniser body
Thrust pieces

3rd/4th gear
A two-cone synchronisation system is used for these two gears.

Intermediate ring
Synchro ring
Shift sleeve
Synchroniser body

5th/6th gear
A single-cone synchronisation system is used for these two gears.

Synchro ring
Shift sleeve
Synchroniser body

Reverse gear
Like 5th/6th gear, reverse gear also features a single-cone synchronisation system.

Gearshifting

The M32-6 manual transmission also has a cable gearshift. The individual gears are selected by means of a central gearshift unit.

Mark for the M32-6 manual transmission
The mark for the M32-6 manual transmission consists of a bar code and a combination of numbers.
The letters and numbers located below the bar code have the following meanings:

M32Transmission type
O“Opel” design
FAM2Engine family
3.941Ratio
CWheel set
XXXXXXXXSerial number
NRTransmission code

Transmission fluid
The M32-6 manual transmission uses the same transmission fluid as the F13 / F17 / F17+ / F23 / F25 / F35 and F40 transmissions.
The transmission’s fluid fill quantity is 2.4 litres.
Container sizeCatalogue numberPart number
1 litre SAE 8019 40 7689 120 541
60 litres SAE 8019 40 7109 194 349

Technical data
The maximum input torque for the M32-6 manual transmission is 320 Nm.
The weight of the M32-6 manual transmission is approx. 41.5 kg without fluid.
The overall length of the transmission is 329.5 mm.
Transmission ratio
EngineZ 20 LEL
1st gear3.818
2nd gear2.053
3rd gear1.302
4th gear0.935
5th gear0.744
6th gear0.614
Reverse gear3.727
Output ratio3.94