1969 Series IIa - no third gear

[SafeAirOne]

So, I found a series III transmission for my series IIa. I understand that the bellhousing bolt pattern will be different so I will need the series III bellhousing and clutch release assembly?

No. The bolt pattern will be different only if one was out of a 6-cylinder and the other out of a 4-cylinder. If they were both 4-cylinder transmissions, they will mate up with a 4-cylinder engine.

The only thing that is series-dependent is the clutch actuation method:

The SIII has the slave mounted right through the front of the bellhousing and points aft and DIRECTLY actuates the clutch throw lever on the inside of the bellhousing. (third diagram down on this page).

The SIIA has the slave mounted vertically beside the bellhousing and pushes a bellcrank connected to a rod that runs inside the bellhousing (top 2 diagrams on this page).

If you found a SIII transmission out of a 4-cylinder, you should just be able to install it and run a line from your existing clutch master cylinder to the slave on the front of the SIII transmission (if it comes with the slave. If not, just buy one and plumb it in).

You might want to check on this, but I think the different master cylinders will work equally well with either the SIIA or the SIII slave cylinders displacement-wise.

Not all series III's had 6-cylinder engines. In fact, most didn't (besides NADA). just ask the seller if the transmission was out of a 4-cylinder rover or a 6-cylinder rover.

[WilsBoar]

Thanks for the great rundown Mark. I will see what engine the series III had. I appreciate the info.

Derek

[Jim-ME]

Can one switch the bell housing/slave from a 2a on to a 3 to keep the original 2a clutch system?
Jim

[WilsBoar]

Hmmm, good question Jim. That may save some effort and $$ for me on this evolution.

[SafeAirOne]

Can one switch the bell housing/slave from a 2a on to a 3 to keep the original 2a clutch system?
Jim

I couldn't say for sure--I've never done it, but I'm sure somebody here knows one way or another. I suspect the input shafts and bellhousing mounts are compatible.

[daveb]

I'm just reading this now after replying to the bellhousing question in your other thread. I am running a SIII trans with a IIa bellhousing. So yes it is possible. I would try to fix what you have before dropping any coin on a replacement box. Changing the 3/4 synchro detent springs can't be that hard. I have watched somebody do it and I never even got tired

[Jim-ME]

I need a to completely rebuild my trans as mine is really noisy in all gears. I am leaning towards a rebuilt 2a but you never know what might be available.
Jim

[WilsBoar]

Just found 2 SII gearboxes close by. One from a 1958 109 and another from a 1966 88.
From what I have read here, the SII should mate up with my SIIa hardware.

How far am I moving backward if I don't use a SIIa gearbox? Assuming that the gearbox is in decent shape and won't need rebuilt immediately.

[yorker]

Assuming that the gearbox is in decent shape and won't need rebuilt immediately.

Assuming that it will be just as good as anything else would be.

[I Leak Oil]

Assuming it's original to the truck, I'd go with the '66 gear box and not the '58. The early box, being an earlier suffix, is a) potentially weaker because of the smaller layshaft components and b) will be harder to find parts for. The later box should have some of the updates as it relates to the layshaft.