Thread: IIA and III gearboxes the same?

The gearbox was basically the same from early Series 1 to the end of Series 2a, with progressive relatively minor changes (but you need the suffix letter on the box when ordering parts.

While the Series 3 gearbox is basically interchangeable there are two significant changes:- The gearbox is all synchromesh, as against synchro on 3/4 on the earlier boxes; and the bell housing and clutch release mechanism are different.

The Series 3 box can be installed in the 2a, either by fitting the bell housing from the 2a box (only later 2a boxes), or by changing the pipework for the clutch and using the S3 pressure plate. But the S3 bell housing can only be used if the 2a and 3 are both fours or both sixes - the bell housing pattern is different between four and six. You can check which the Series 3 was by the position of the gearbox - the six has the box further back.

John

Thanks for that John. So if i pull the 2a and mount that bellhousing on the S3 box, I can get that extra ease of he extra synchro and the overdrive. It is a 1970 2A so guessing that is 'late'?

Just a matter of making sure the S3 box is OK now.

Originally Posted by Craigb

Thanks for that John. So if i pull the 2a and mount that bellhousing on the S3 box, I can get that extra ease of he extra synchro and the overdrive. It is a 1970 2A so guessing that is 'late'?

Just a matter of making sure the S3 box is OK now.

Yes, always provided the box in the 2a is the original!

John

Like John said, you can swap the bell housing over if they are both fours or both sixes. if you are not sure what you have, look at the top of the bell housings the diesel and petrol fours have a single stud hole at the top centre and the sixes have two holes either side of top centre.

I think your swap should be ok age wise, but the earlier bell housings did have smaller bearings for the layshaft.
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Thanks for the advice. And anyone suggest must replace parts while the gearbox is out that always wear? Or are they pretty robust and if i can't see any obvious wear just seal up the oil leak bits and pop it in? And this is a ute, so easiest to remove the roof, floor etc and take it out that way? The detent springs on both boxes seem weak, is this just how they are or these should be replaced?

Any help greatly appreciated.

Originally Posted by Craigb

And this is a ute, so easiest to remove the roof, floor etc and take it out that way? The detent springs on both boxes seem weak, is this just how they are or these should be replaced?

Any help greatly appreciated.

Catch up with this thread, 'Daihatsu diesel conversion problems' by Tim Jones " --- on the west cost of SA near Elliston"

Daihatsu diesel conversion problems

Fit a bearing kit, inspect first gear, reverse gear, reverse idler, teeth for any marking and the phosphorous-bronze bush that the second and third gear runs on, take particular notice of the surfaces that the needle roller bearing run and make sure the preload's are spot on by selecting the correct shims/thrust washers.

Don't use EP90 diff oil in the gearbox as the Aluminium oxide in the oil over time, causes electrolysis with the phosphorous-bronze bush, use a straight 50 mineral oil.
If either box has run dry of oil, it usually results in the phosphorous-bronze bush binding inside one of the gears and breaking, if this has been done for a while, the two locating pins that lock the bush to the shaft shear off and the mainshaft can wear badly under where the phosphorous-bronze bush sits.

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