Ode to the Aussie 4 Speed

[HK1837]

I had a 202 with W55 and 3.55 in a HJ sedan. It was fine for towing, and fine for highway. Big gaps in between gears though, but nicer than an aussie box. I've said it before here too that you can cheat a little with aussie 4spd's and run an M22 gearset with a 2.78/2.6 or 3.08 diff. 1st gear at 3.74:1 feels like a Celica or Supra but they still feel OK in top at highway speeds. Not the greatest combo for around town regular driving as there is big gaps in between gears like a Jap box. But OK for a Sunday cruiser that does mainly highway trips. It is good having the tall first if you have to put your car on a parking hoist or reverse into a shed regularly like I have to - this is where the TH400 and LSD in the HJ Prem are great, i'd never reverse a 308 manual up the driveway (Agro can vouch for how awful it is!).

[agr071]

i'd never reverse a 308 manual up the driveway (Agro can vouch for how awful it is!).

Yes i can vouch for this one.
It was bad enough doing it in my 308 auto and it has a 2.78 diff and 15" rims with high profile tyres.

[James]

My first car was an HQ ute, 3 speed Impala shift, there were not many others who could change from 1st to 2nd without causing a major lockup.

I also have a story about the old "first and reverse" lock up scenario with a four speed ( different HQ ute but 15 years later) .
It just happened to be at a boat ramp retrieving a tinny and the weight of the car rolling back made it impossible to get out of reverse until the car's weight was taken off the gearbox. The tide was coming in of course and there's a heap more to this story and the panic that followed but I managed to get towed out by a V8 Range Rover and it's ten foot tall driver (he'd had a few rums).

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One thing i'll give them is they are easy to rebuild, I used to do a few of them. At least I thought they were easy, till I built a Muncie. Then I realised that the aussie 4spd is like a scale model of a real gearbox. On a muncie you stick 2 fingers down the layshaft tunnel to put the needle rollers in place, and the needle rollers are like pencil size. You could break someone's skull with 1st gear rather than give someone a nasty scratch with an Aussie 1st. And the layshaft belongs in a porno, or on a donkey.

Can't the M21's internals be "worked" to house a donkey size layshaft, needle rollers etc?

[agr071]

Slightly off topic, but is the 3 speed just as weak as the 4 speed?

[HK1837]

Yes they can, but nowhere near a sized Muncie layshaft. I think they use a smaller shaft from a top loader or something like that. A Muncie layshaft and needle rollers would probably be bigger in diameter than the trough of the gears on 1st/Reverse on the aussie boxes. Aussie boxes last a lot longer if you use a bronze bush in the cluster, a bigger circlip on 1st gear and a new or aftermarket shifter. If I was going to run a 4spd in a HQ-WB I'd be fitting a brand new Muncie with 4th gear overdrive and 3.36:1 diff gears. You can actually fit a Hurst shifter and not foul the floor, and one of these boxes will fit using a HT-HG 253/308 Saginaw bellhousing which looks just like an aussie 4spd one and will take the standard HQ-HZ clutch setup. Only odd one out is late HZ with full cable clutch where you have to run an aftermarket belllhousing.

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Slightly off topic, but is the 3 speed just as weak as the 4 speed?

No, these are heaps stronger. Lots of speedway blokes use them. Aussie 4spds normally wear out the cluster end with 1st and reverse on it and 3spds don't have this problem. They also don't have the 1st gear circlip issue, plus they don't use the awful Aussie shifter. These three things alone cause probably 90% of aussie 4spd failures. Often breakages are because of wear elsewhere in the box.

[agr071]

Does a 3 speed would have different ratio's compared to Trimatic/Turbo.

Might have to find a 3 speed and floor shifter to keep in case i decide to put out the trimatic and put a manual back in the HJ.

[HK1837]

Most M15 3spd synchro are the same ratio, except for a close ratio one fitted to HT V8. 1st gear on the normal ones is about the same as an M20 aussie.

3.07:1 1.68:1 1:1 Reverse: 3.59:1

Where the 3spd is better is its reverse. You can get away with running a 3.08 (or even 2.78 behind a 308) then 1st will be about the same as M20 wirh 3.08 but reverse is lower, whereas all aussie 4spd have reverse the same ratio as 1st. You can use an aussie 4spd shifter with one too, reverse is where 1st is. This is how 3spd Bedfords were done. From memory I think the 4spd extension housing fits straight on a 3spd so the shifter fits exactly as per on a 4spd and uses the same shift rods etc. Only hassle is the reverse switch, it'd have to be something like the Bedfords used.

[Robbo]

Are these Aussie 4 Speed boxes, the same boxes that were used in the LJ series Torana?