SERIES GEARBOX SWAP
The gearbox in my Series IIA is so noisy the bearings emit a hight pitch whine. I have the chance of buying a Series III gearbox that is known for being good, and I have travelled in the vehicle and heard it running. I assume the Series III gearbox is better than the series IIA version and that it will drop straight into the Series IIA. Or are there any problems I need to know about?
Ian Robson
The Series III is an all-synchromesh unit and is the stronger gearbox. It has a tendency to jump out of gear when worn, though the suffix D (serial number) onward had uprated gears and improved synchromesh and is the best of the lot.
Assuming both of the vehicles have a standard 2.25-litre engine, the bellhousing should be the same, in which case the gearbox will fit to your Series IIA engine.
However, the Series III clutch slave cylinder is on the left side (looking forward from the rear of the vehicle), whereas the Series IIA has the slave cylinder on the right hand side. So the Series III slave cylinder will foul the chassis which has a strengthening web on the left side of the engine crossmember just behind the flywheel housing.
You will need to trim the web back in a smooth curve, leaving about 25mm of material between the cut-out and the chassis side rail. Use the clutch piping from the Series III if possible, and also the clutch hose and the bracket on the engine that secures the hose. Otherwise, use new parts to connect the hydraulic circuit. You will also need to use the Series III clutch pressure plate assembly.
Ed Evans