M32 Gearbox Info


How To Change Gear Box Oil

Pictures from doing mine this morning. I watched someone do mine last time, and this is a great guide.

It was last changed 18 months ago


DSC_5663 by Matt Worthington, on Flickr


DSC_5664 by Matt Worthington, on Flickr


DSC_5665 by Matt Worthington, on Flickr

Fill level on the front of the box

DSC_5666 by Matt Worthington, on Flickr

Drain on the rear

DSC_5667 by Matt Worthington, on Flickr

New gearbox oil (2.3 litre needed for a change)

DSC_5668 by Matt Worthington, on Flickr


DSC_5669 by Matt Worthington, on Flickr

Old Oil

DSC_5671 by Matt Worthington, on Flickr

New Vs Old

DSC_5672 by Matt Worthington, on Flickr

Even after just 18 months since it was last changed, gear change is a LOT smoother with the fresh oil in.

Tools needed are: Jack & axle stand, 17mm socket (wheel nuts), Torque wrench, ratchet, extension bar, 10mm spanner, 1/2'' socket, 10mm Allen key, T50 Torx socket, funnel.


Former Staff
Senior Member
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



Main issue with the box is the bearings in them. They all use the same bearings, however, it's the torque which seems to be killing the boxes, or real serious abuse. The CDTI's seem to eat them, and so do tuned VXRs, as the torque goes through the roof with a remap. I've been on the VXR site since I bought mine, and the only people who seem to be having issues are people running stage 2+ and most seem to be on the newer 2008+ models.


Yes, they are quite clunky boxes. First real signs of wear are forward/backward movement of the gear stick when applying / lifting off the throttle. Mainly noticeable in 5[sup]th[/sup] and 6[sup]th[/sup] gear.


Former Staff
Senior Member
Yes, they are quite clunky boxes. First real signs of wear are forward/backward movement of the gear stick when applying / lifting off the throttle. Mainly noticeable in 5[sup]th[/sup] and 6[sup]th[/sup] gear.

which i havnt got...thank fook....


Yeah, same here. I'm really paranoid, but TBH, I hardly drive my car, and when I do, it's not very hard, so should be good with the regular oil changes. Plus vocky knows these boxes inside out (literally!) in case it does break