series 2a-3 gearbox differences

[army2a]

hey guys, what are the differences between the series 2a and series 3 gearbox, my understanding was the series 3 has synchros on 2nd gear but is a weaker box than a 2a. im keen on having synchro 2nd but if the gearbox is going to be weak i wont worry about it. My engine is a 2.25 petrol.

[Slunnie]

I'm sure the S3 gearbox would still be strong enough though wouldn't it? I'd be thinking of driving pleasure also.

[pop058]

others will add more detail, but the 2A box has syncro on 3rd & 4th where the S3 bow has syncro on all forward gears. Not direct experience, but I believe the latter 2A box (at least) is a stronger box than the S3. Not that it would make to much difference behind a 2.25.

HTH

[Lotz-A-Landies]

The 1st and 2nd mainshaft gears are narrowed to about half the thickness that they are in the SIIa and SI boxes, although the SIII box has one piece layshaft cluster so solves the weaknesses in the earlier boxes.

If you are running a 2 1/4 litre engine the SIII box is probably strong enough, particularly on an 88".

If you do go to the SIII box, make sure you get one with the lattice reinforcing in the housing over the reverse idler shaft, this is a known weakness of the early SIII housings.

BTW: It is possible to swap the bellhousings and clutch throwout from the SIII type to the original SIIa type.

[vnx205]

My Series III LWB gearbox was still going at 300,000km. How much stronger does it need to be? :)

[Ozdunc]

Driving a 2a box isn't a big deal. You can drive it without double de-clutching.
DDC just makes the changed down from 3rd to 2nd a bit easier, but if you don't hurry the box and aren't brutal with it, it actually changes quite nicely.
And for the most part you'll be in 3rd and 4th anyway.

[JDNSW]

My Series III LWB gearbox was still going at 300,000km. How much stronger does it need to be? :)

Depends on who is driving!

The Series 3 box is of adequate strength for the original engines, but stands abuse less than the later 2a boxes, but is perhaps more prone to minor problems than the earlier box. And is also more expensive to overhaul - it has more bits!

My preference is for the 2a box, but then the car I learnt to drive on had no synchromesh. But my sons had little trouble learning to drive the 2a after learning on all synchro boxes.

John

[isuzurover]

My Series III LWB gearbox was still going at 300,000km. How much stronger does it need to be? :)

You would understand the concept of an outlier better than most ;)

[Cliffy]

Nothing wrong with the S3 box and a bit more civilized too.

[korg20000bc]

I'm wondering about doing a similar thing but the other way. I'm looking to replace a knackered 2a engine out of a 2a and replacing with an engine from a s3. The 2a gearbox is fine.

What would need to be considered in this change?

[JDNSW]

S3 engine bolts straight in, except the pressure plate needs to be changed. If it is an early S2a with the upwards exhaust outlet on the manifold, you can either swap manifolds or use a late S2a/3 front pipe. Alternator will require the wiring to be changed slightly - and if it is a pre-67 2a, you need to change to negative earth to suit the alternator, and probably not a good idea to run the charging current through the ammeter.

Carburetter and linkage may also be different, but you can adapt this fairly easily. Again, with an early S2a or a late S3, there could be minor differences in fuel line fittings, but easily dealt with.

John