How to tell a V8 M21 on the ground.

[mauser]

Cool thanks Adam. Which selector is it to put it in first gear? One closest to the input shaft.

Mauser

[thatotherguy]

apart from ratios is there any difference between an M20 and M21?

[HK1837]

apart from ratios is there any difference between an M20 and M21?

Input shaft (4th gear), cluster gear and 3rd gear. Rest is the same (V8 and 6cyl differences aside).

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I was wondering the best method to determine which gearbox it is from looking at one on the ground.

I was led to believe ages ago an M21 had two rings in the input shaft over an M20. Another way is to put the box in first and count the turns??


Mauser

Also, you won't find a 6cyl M21 unless someone has made one. Only a very few cars ever had them (possibly only Repco Rally Commodores).

[mauser]

Thanks Adam and HK for that. Picked up a M21 local so saved me the shipping costs and risk of buying one elsewhere. The parts just to fix another one had easily tipped into $800 bucks with associated cluster and bits.

The box was supplied as a spare with an AusCar years ago and the guy never used it and is moving so was cleaning out his shed. It has bolts with some type of wire seal inter-twined around them. Looks clean as though it hasnt been in a car since a re-build. Right ratio in first from your advice, it has the two rings ground on the input shaft and feels good. Hopefully nothing major wrong inside but thats the way it goes.

The shifter I got with it is slightly more laid-back than the one I have. Is the Commodore M21 shift slightly different from the HX-Z one with the rubber joint in it? (I realise the HQ had a solid chrome shifter but oh well..lol)

These gearboxes are getting harder to come by now unless they come in a bucket. Wont be walking past any $50 ones at a swapmeet anymore. Just need a bellhousing for the rat trap now as this one came with a cable setup and fork.

Mauser