A bit more info i found online.
M32 6-speed manual transmission. 1.9 CDTi & VXR
Bearing failure on the M32 gearbox is very common.
Typically you will notice a whining noise when cruising on the motorway in 6th gear. The whining will come and go as you press and release the accelerator. When the bearings wear even more, the gearstick will begin to move as you press/release the clutch in first gear.
My own experience indicates that just one bearing fails
Failed bearing is at the top of the photo
Excessive play and loose rollers
Bearing becomes pitted due to metal fatigue
Replacement of this bearing, will usually rectify the issues with gearstick movement and whining.
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.
1 Upper main shaft 3 Lower main shaft
2 Input shaft 4 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 gear Upper main shaft
1 1st gear gearwheel 5 3rd/5th gear gearwheel 8 4th gear gearwheel
2 2nd gear gearwheel 6 6th gear gearwheel 9 Reverse gear gearwheel
3 5th gear gearwheel 7 4th gear gearwheel 10 3rd gear gearwheel
4 6th 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