[Gwagensteve]

Kicking around an idea and I’d like input.

How about running a manual FWD transaxle in place of a transfer case

This would provide a low range of 1st gear X final drive in the transaxle =plenty
High range is overdrive X final drive in the transaxle = something close to the reduction of 6.5’s in high range
And intermediate ratios.

In an ideal world an airlocker (or electric locker) in the transaxle would provide digs and could be tied to a cutting brake so one lever unlocks the locker and applies the relevant brake

Cons- weight, complexity, lots of custom stuff.
Pros- as above.

[Gwagensteve]

Oh- I was looking at the diesel i30 transaxle with (maybe) and auto final drive (3:1) his gives a 1.788 “high” range and lots of splits down to something like 10.something low range.

[sideways]

I've pondered this too, for a tractor build. It would have to be something pretty small to fit in the trans tunnel of a vehicle relevant to this forum!

I reckon weld the diff and just run free wheeling hubs for 4wd/2wd selection. Obviously you wouldn't have digs but it would have to be very robust to take that. LT230 centre diffs die when dug like that. I've seen pictures of an LT230 case exploded from an attempted dig.

Use the trans out of a Colt (they have high/low) with a 5 speed driving it and you have 50 forward gears to choose from!

What's the application you're picturing? Or are we just vapor building here?

[tanshi]

lt230s dig fine with a part time swap done on them. wouldnt be hard to do similar to a transaxle diff. but yes you would only end up with one digg either front or rear but not both.

[Gwagensteve]

Not entirely vapour. I’d like a taller low range but want to retain my AW-4 and crawlability. I’d like to do more with digs etc but the trail tough disconnect is slow and clunky which makes it annoying to use, we’re all putting $$ into sierra transfers but they have limitations.

I get the death of centre diffs in heavy car/high HP high speed digs to build tyre heat. That’s not what I’m chasing- just smooth control of drive for positioning. The procedure with the TT disconnect was too slow to be bothered with. (Stop, bump neutral, fiddle with lever, get nothing, bump reverse, bump drive, get lever in position, move 3 feet, repeat process.

[Eddy]

Works well.
We built a 4WD mini articulated tractor way back, using a 850 mini engine and trans, driving a pair of Austin A40 diffs. Worked a treat.

Next up was a datto 180B diff, mounted sideways, onto two more 720 Datto diffs, chain driven off a Honda XL350 engine, four wheel steer.

We then expanded on the idea and fitted a Magna unit onto a Daihatsu F55, driven by a 1600 toyota through a 5 speed box.
25 forward gears

[sideways]

Nice! Got any pics?

[Gwagensteve]

Cool.
I know various ideas have been tried in off-road applications, It’s really the new 6 speed/double overdrive transaxles that might still allow road use.

[ZUZUKI]

I'm probably missing something....how is proposed drive going to be turned at right angles?
If you go north/south engine, rear output gearbox, to a welded locked IRS diff, to a transaxle mounted north south, that's whew, for as you say Steve, weight & complexity!
Would probably end up with tailshaft alignment issues.

A crazy idea I had along these lines, is Subaru flat 4 sideways in the car, with attached front wheel drive transaxle, (the outputs for the formerly front driveshafts would be then north/south & about at the longitudinal centreline of the car) locked diff with nothing out the 'front' & drive via the formerly P/S driveshaft output (now facing the rear) to a combined transmission/transfer case (Mitsubishi 'Super Select' maybe?).
Still has a weight issue, but would probably end up short enough to fit in a vehicle of moderate wheelbase. Could be tricky to package the front tailshaft & diff, so the next thought was to use subframe/chassis mounted IRS diffs with driveshafts out to boat 'V' drive gearboxes (used 'overdriven) to end up with long driveshafts out to the wheels (allowing large wheel travel), these shafts would be staggered like the Ford F series 'twin I beam' front suspension, then use wheelhub drop boxes from the rear of an early VW Kombi (but how to make them steer?) maybe use Pinzgauer hubs?

Then I stopped thinking, because my brain hurt. There would be some crazy low gearing numbers out of a set up like this, which is not going to be useful, it would be silly heavy, and, really just silly.
But fun to think about.
Rgs, Michael

[Eddy]

sideways wrote:

Nice! Got any pics?

nah .. sorry. late seventies -early eighties. We were too busy driving the shit out of-em to take time out for pitchers

[Eddy]

ZUZUKI wrote:

I'm probably missing something....how is proposed drive going to be turned at right angles?
If you go north/south engine, rear output gearbox, to a welded locked IRS diff, to a transaxle mounted north south, that's whew, for as you say Steve, weight & complexity!
Would probably end up with tailshaft alignment issues.

see below ...

ZUZUKI wrote:

A crazy idea I had along these lines, is Subaru flat 4 sideways in the car, with attached front wheel drive transaxle, (the outputs for the formerly front driveshafts would be then north/south & about at the longitudinal centreline of the car) locked diff with nothing out the 'front' & drive via the formerly P/S driveshaft output (now facing the rear) to a combined transmission/transfer case (Mitsubishi 'Super Select' maybe?).

pretty much covers your query

CV joints can take up some alignment issues.

A transaxle unit is a similar weight, maybe lighter than a Transfer case and gearbox, so not really a problem.
Alignment issues can be covered by mounting the unit off centre to the right, and either under the seat area, or change to left hand drive if you want to sit lower. In the daihatsu we did have the drive shafts, (on CVs) running at a fairly wild angle, even tho the box was partly under the driver's seat.
We built a couple diffs from toyota diffs, modified to relocate the pumpkin over to the left side from the right side, which would have allowed the T/A to come back to centre line, but then we moved on to other stuff and the whole thing got sold on (to a weed spray contractor)

[Gwagensteve]

You're way, way overthinking it Michael.

for reference, here's a couple of photos of a (generic) i30 manual transaxle.





The overall shape and offset is not terribly different to a larger transfer case. It's probably smaller and lighter than an LT230 (admittedly not hard, but still) The intent would be to install it in roughly the same location as a standard transfer case with a short jackshaft. It's clearly much smaller than a 4 speed atlas, which offers similar ratios but a direct high range.
Yes, it has an annoying bell housing pattern to work with, some of which could easily be removed. The offset is still to the RHS so will broadly align with Sierra diff centre locations (and this isn't a new thing - the Thai guys use transaxle powered Sierras with Volvo diffs which are offset the same as Sierra. )

The linkage junk can be massively simplified. In this application we probably only need 1st, 4th and 6th gear. We obviously don't want reverse.

I don't know what a second hand i30 6 speed transaxle is worth (and there might be other better options) but when we add up what we're spending on gears, mounts, a rear disconnect, maybe a twisted T shifter or twin sticks, and now the cool kids are getting all excited about $1K billet case 1/2's, we're pouring a lot of money into a transfer that still, arguably has too small an input gear to live happily, along with that stupid countershaft design.

Anyway, sure, it's bench racing an idea that might inspire someone (or me) to pursue it.

Oh, and like any idea, it's not remotely original as Eddy and a UK guy on Pirate who is building a independent suspension/portal trials car running a 1000cc motorbike motor and transmission into a transaxle

[Eddy]

Gwagensteve wrote:

like any idea, it's not remotely original as Eddy and a UK guy on Pirate ...

and thousands of others.

I got the idea after hearing about some other bloke doing it after he saw someone doing it. Been happening since the mini first appeared.


That pic of the i30 got me thinkin ...

Is that pic correct? not flipped.

If it's correct then the whole thing gets a touch easier, coz the output would already come to the side ya need it to be.

[ZUZUKI]

Ah, I knew I wasn't working it out right - those photos make it make more sense.

Yes, I was overthinking my thoughts of the very complicated & totally impracticable thing, which is why I stopped thinking - never had the remotest chance of considering cobbling something along these lines together.

So, sorry being a bit frivolous with the sort of idea you are floating - which has real merit, unlike my mash-up.

Rgs, Michael

[jono165]

I like this idea. I wonder if there’s something out there with a removable bellhousing.

Would the idea be to have some sort of slip yoke eliminator so there is a stub shaft secured in the transaxle and then use a normal driveshaft?

There’s more and more 6 speed transaxle becoming available to do this with.

[jono165]

Or there’s options like a Toyota AE95 transaxle or similar which have a centre diff lock and I think the front part of it is removable so it could just have one forward output or a PTO for a winch or something.