Series 2a gearbox into Series 3 lightweight?

[Betsy]

I have a series 3 LW, fitted with a 2.5 petrol engine, and the gearbox is kaput!. I have a very good gearbox and transfer box from a 2a that I would like to install. What bits will need to be swapped over to the 2a box, and which clutch should I use? I am sure this is a reasonably simple swap, but any advice would be welcome.

[Soren Frimodt]

Not that straightforward I'm afraid.. Well bolting it up is, every bolts sits the same place and you can use whichever clutch that bolts up to the 2,5 engine there's no difference here on the SII and SIII. BUT the clutch slave-cylinder sits at a very different place and you will have to make up new lines/ get some from a SII.

And in a SII there's a hole from which you gain access to bleed the aforementioned clutch cylinder. Not sure how much room there is for it in a LW either.. But it can be done no doubt about it, but it isn't just a quick swap. And with the SII box you will loose the syncro'ed 1st and 2nd.

[TheRecklessEngineer]

When I built my S3, I took the bell housing from a knackered S3 gearbox and mounted it on a 2A gearbox.

Not too straightforward, but not that difficult either. Once together, it bolted straight up.

[Betsy]

Ok, thanks for that. I was expecting to have to swap bell housings, and its good news that the 2.5 clutch would work.

With regard to loosing synchro on 3rd and 4th, that no loss then! the S3 box has eaten its synchromesh already, and jumps out of gears for fun. The long term plan is to rebuild the original box over the winter, and eventually swap it back.

[Phil Hancock]

I have a series 3 LW, fitted with a 2.5 petrol engine, and the gearbox is kaput!. I have a very good gearbox and transfer box from a 2a that I would like to install. What bits will need to be swapped over to the 2a box, and which clutch should I use? I am sure this is a reasonably simple swap, but any advice would be welcome.

You use the clutch thats appropriate to the bellhousing, so if you use the 2a box with its original bellhousing then you will also need a 2a clutch.

[Soren Frimodt]

Why is that Phil?

Not doubting your wealthy knowledge, but I had a 2,5TD on my SII box and ran a HD clutch kit for 200TDI, 9,5" dia. And that worked fine.. Can't see where the problem would be?

[Snagger]

You will be able to retain the SIII clutch system if you swap the bell housings. Keep the existing pinion in the SIII bell housing and fit the matched gear from the SIII lay shaft to the SII lay shaft to ensure good mesh.

The 2.5 engine will need its clutch drive or friction plate replacing with a SIII item (to match the gear box pinion splines), but the flywheel and clutch pressure plate are compatible with the SIII parts.

You will lose 1st and 2nd synchromesh, not 3rd and 4th. Personally, I'd sell the IIA box and use the proceeds to rebuild the SIII unit - it's a much nicer drive and is better off road because you don't lose as much momentum from double de-clutching.

The 2.5 is a nice mode, though.

[Betsy]

Thanks Snagger, the 2.5 engine is already fitted and running, and mated to a knackered series 3 gearbox, so if I understand you correctly, I need to take the bellhousing and associated pinion and layshaft gears off the knackered box and fit to my good 2a box. Of course, whilst its all out I will replace the clutch anyway, with a unit the same as the one thats already fitted.

This swap is temporary in order the keep the vehicle on the road whilst the S3 box is rebuilt by myself over the winter, I just happen to have the 2a box in my shed, and I know its good because I rebuilt it a few years back as a spare for my 2a.

[Phil Hancock]

Why is that Phil?

Not doubting your wealthy knowledge, but I had a 2,5TD on my SII box and ran a HD clutch kit for 200TDI, 9,5" dia. And that worked fine.. Can't see where the problem would be?

A 2a diaphragm clutch has a boss on the middle of the cover fingers which makes the cover taller, using a S3 cover will put the release mechanism at or over the limit of travel for releasing the clutch, also from my experience of driving a 2a had had a(vertually worn out) S3 cover in it the clutch was heavy as the shape of the levers meant that the contact point was at the outside of the release sleeve so closer to the diaphragm pivot point than the correct boss would put the contact or the S3 release brg would contact the diaphragm.

[Soren Frimodt]

A 2a diaphragm clutch has a boss on the middle of the cover fingers which makes the cover taller, using a S3 cover will put the release mechanism at or over the limit of travel for releasing the clutch, also from my experience of driving a 2a had had a(vertually worn out) S3 cover in it the clutch was heavy as the shape of the levers meant that the contact point was at the outside of the release sleeve so closer to the diaphragm pivot point than the correct boss would put the contact or the S3 release brg would contact the diaphragm.

Hmm.. Interesting. I can see the logic in that Phil, although I never had such problems. LR tolerances maybe saved me @rse?