With the chassis and engine gone, there’s a lot more space in the garage, so time for a bit more of a tidy up and start stripping the gearbox down.

The Series gearbox didn’t evolve much between 1948 and 1971 but there were some notable milestones along the way.

Early Series 1 gearboxes saw common failures in the mail shafts, chipped teeth and damage to second gear (due to lack of syncro between 1st and 2nd). These were exacerbated with the introduction of a larger engine in 1958.

1961 saw the internals reworked to  better accommodate the increased power of the 2.25L and (later) the 2.6L engines.  By 1971, the gearbox was fully synchronise and had a completely redesign of the clutch release mechanism.

The gearbox in LGL is a suffix D unit and comprises the following:

  • 8 forward gears, 2 reverse.
  • No synchro between 1st and 2nd (double clutching is required to make a smooth gear change)
  • Synchro between 3rd and 4th gear
  • Has the earlier (considered more robust) clutch release mechanism.

All this is housed in 2 gear boxes. The Main Box and Transfer Box.

The gearbox didn’t sound all that bad on the short period I was using the vehicle before the rebuild started but I am assuming to have to replace most of the gears. All bearings, seals and gaskets will be replaced

Bell housing removal

I made the mistake whilst rebuilding a Series 3 gearbox, of first removing the handbrake assembly (on the rear output shaft), this meant there was no way to lock the gearbox and prevent it rotating…. an essential point when needing to remove nuts on gear shafts; this time I “RTFM” 🙂

Step one is to remove the bell housing. This is where the gearbox mates with the engine and houses the clutch. The splined shaft in the centre engages with the crank at the back of the engine.

Bell housing cleaned with brake cleaner fluid. Clutch release housing in position
Clutch release mechanism removed revealing the primary pinion (top)  and main shaft bearing (lower). Both bearings have significant play in the them. The 4 large nuts at the back of the bell housing now need to be removed along with the main shaft nut
Bell housing removed revealing the mainshaft (top) with roller bearing and end of the 3rd, 4th synchro in view. Layshaft (bottom) with contrast gear in view
The backside of the bell housing showing the primary pinion (top) and the layshaft bearing (bottom). The primary pinion will engage with the mainshaft in the picture and above

Clutch Release Mechanism

The more complicated of the two release mechanisms used in the Series land rover, it is considered the more robust.

When the cutch pedal is depressed, the shaft on the left of the housing is rotated, pushing the clutch withdrawal sleeve (the round disc between the 4 bolt holes) onto the face of the clutch and disengaging it for the engine.
Flipped view… This time, shaft on the right. Fork in the middle and the clutch release bearing inside the clutch release sleeve