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I tried to search your profile for other posts, but the board software is fighting me. Do you have a thread somewhere on it?

The cut up oil pan is going to be "cleaned up" back down to just being a diff housing? With the wheel forward positioning plus your engine setback, it's well in front of the engine, correct?

I found this and there re links to pictures.
http://locostusa.com/forums/viewtopic.php?f=5&t=13719

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I've been mulling this over for a while now. My fantasy would be to build a rear mid engine AWD with a similar setup to a Lambo. The problem, well one of many, is most transfer cases have a rear wheel torque split bias which wouldn't normally be a problem but now the engine is in the back with the crank output in the center of the car, reversing the orientation of the transmission and transfer case look at this and you'll see what I'm talking about http://www.pirate4x4.com/forum/showthread.php?t=406196 Now what was the rear wheel output of the tcase is now the front wheel output and now the car would have a front wheel torque split bias., probably not good for this setup. After a little more research I found that a Rover Freelander has a separate/divorced viscous coupling unit that could be used between the output of the tcase and the front diff and one could use a locked tcase and not worry about the torque split bias. I know this is how Lambo and VW set up their awd systems but is this a true awd system or is it a 2wd until the rear wheels slip and the coupling is engaged?
On another note the diffs all have to be flipped to work in this configuration and the problem with that is now all your diffs will be high pinion and potentially suffer from oil starvation. Some Toyota front diffs are high pinion so they would be good candidates for flipping, going from high to low pinion and they also make reverse cut ring and pinion gears. So one could take a high pinion, reverse cut R&P gear front diff flip it and use it as a rear diff and take a standard rear diff, flip it and use it as a front diff. Why all the flipping and reverse cut gears? If the engine is in the rear with the output towards the center of the car the drive shaft rotation is now counter clockwise looking from the front of the car. Does it all make sense? I'm putting this out here to see if my thinking makes any sense or is fundamentally flawed.
Thanks
Justin

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This buggy (mid engine awd) from my country. May by used audi quattro gearbox end of which transfer case

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Never be afraid to do what you dont learn, remember: amateurs built the ark - Professionals built the Titanic.

I'd thought about that setup too but I don't have the fab skills to build a "transfer case" like that. Probably simpler in the end to do it that way but a lot more machine shop intensive. Do you know if there are kits or packages that one can buy to convert a trans-axle to a setup like this?

P.S. The problem with this setup is the same as stated earlier is how would one change the torque split bias in the transmission transfer-case? I think Subaru has something like a 33/67 f/r bias and with a setup like above that would switch the bias to 67/33 f/r, not good for a rear mid engine set up.

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about diff flip to reverse rotation is all sence, i have same idea. But there are two but trouble: flip diff trouble with lubrication and and if you change the direction of rotation propeler shaft (from what belong) will broke.
why not use schematic like ford rs2000 ?
http://www.awdwiki.com/images/ford-rs200-transmission.jpg
but use gearbox like this http://www.awdwiki.com/images/th/ford-escort-rs-cosworth-gearbox.jpg awd or 4x4 with coupling unit (etc freelander) to front. If i good remember with this one chassis configuration needed to flip diff `s and the front use in rear, rear use in front (but I'm not so sure) or to use the diff, which is turning the other way .
Europe is full of such transmissions 4x4, but I heard usa low-to choice. mitsubishi pajero, suzuki Escudo, honda passport, Jeep Wrangler
p.s. don`t forget use same ratio diff or 0.01 tolerance (my car orginal diff has a tolerance)

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Never be afraid to do what you dont learn, remember: amateurs built the ark - Professionals built the Titanic.

Yes that's true if you were to use what was the front diff in the front and what was the rear diff in the rear. However because the whole drive line is reversed the diffs would be reversed as well. Now what was the front diff is now the rear diff and so on. Because of this reversal the rotation remains in the correct direction, ie clockwise for the front diff (was the rear diff originally) and counter clockwise for the rear diff (originally the front diff) Just to clarify I'm thinking of using Toyota 4x4 diffs where the front diffs are high pinion and use reverse cut gears so there is no loss of strength when run "backwards" and no loss of lubrication when flipped. That would be for what is the new rear diff and for the new front diff would use a the same high pinion diff but with regular cut gears and flip it. No oiling issue and the diff are all rotating as designed.
As far as the transmission/transferase I would love the simplicity of using a transmission like the one you linked to but the torque split becomes an issue again that is unless that particular transmission has a true 50/50 or 60/40 f/r split. I looked at the skyline/r32 trans but I believe the torque split is rear biased AND computer controlled, both are not good for this potential project.
Remember I'm trying to figure out how to setup the drive line like Lambo has their setup so the Ford setup wouldn't work for me.
Justin

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I think you need to dig deeper into the "Reverse Cut" gearsets....

I'm pretty sure that the reverse cuts refer to High Pinion setups. For instance, the Ford 8.8 is normally a low pinion std rotation unit. The front axle 8.8 is high pinion reverse rotation. However, it is my understanding that the gearsets won't interchange between the housings, because they've got different offsets.

I'm not absolutely positive of that info. So, a second person doing the research would be good.

JustDreamin

I may be wrong but my initial understanding regarding Toyota FJ front diffs (high pinion) is that the reverse cut and regular R&P gears are interchangeable as long as they are both the 8" gear sets. Not all Toyota diffs are high pinion and the 8" gear sets are available for both. Now I don't know if the high pinion 3rd member will fit in a low pinion housing but I could just flip the high pinion housing.
Right?
Justin

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Let me try to say this more clearly, because I don't think I did a good job......

My research has led me to the understanding that High Pinion = Reverse Cut.
Two different names for the same thing.

Low pinion is the normal standard rotation gearset.

In a front axle application you have 2 choices (assuming normal driveline rotation direction)

1.) Low pinion. Basically this is a "rear" turned around backwards and adapted so you can steer. Pinion is being driven "backwards" from it's normal rotation, but is installed backwards in the truck, so it produces forwards. But it's applying power on the "coast" side of the gear (the weak side). This is what OEM's started using when they were adding power to the front axle, because they didn't have another choice.

2.) Later, gear manufacturers developed High Pinion. This is a new gearset designed with the pinion above the axle centerline (as opposed to below), hence the high pinion moniker. It utilizes a Reverse Cut gear, which rotates the same direction, but now is driving on the "drive" side instead of the "coast" side of the gear. Often these are incorrectly refered to as reverse rotation, but Reverse Cut is accurate.

The 2 designs do not interchange. You cannot put a Std Ring & Pinion in a HP housing or vice-versa. The offsets of the hypoid gear are different. For example, the Ford 8.8" offset is 1.50". So, the Std gear has the pinion 1.50" below axle centerline, and the Rev Cut has the pinion 1.5" above the axle centerline (but the ring gear is in the same location, not flipped over) Gears physically won't mate in the wrong housing (you probably can install both bits separately, ie pinion in the case, ring on diff, just can't put them together because the gears will not mesh in that orientation).

I hope that explanation makes it clearer. Please don't take my word for it though. Search the web and make sure I'm right!

JustDreamin

I think what you'd end up with is a low pinion housing that uses a reverse rotation driveshaft to generate forward motion, running on the "coast" (weak) side of the gear.

Or you could flip a low pinion to a high pinion orientation using a reverse rotation driveshaft generating forward motion, running on the "drive" side. But you'd have to address oiling concerns (since it'd be running upside down).

Not sure if that answers the question, though....

Oh, and I hope I don't sound too negative. I too have thought that a mid engine car with trans mounted ahead of the engine, driving the front and rear wheels through a power splitting transfer case would be WAY cool.

However, the technical challenges (re-engineering a VC transfer case to get the F/R split correct, figuring out front & rear diffs / rotation) are not things that are easily or cheaply done, at least by the methods I've considered.

My VC transfer case of choice would be the BW4472 (used in the Syclone / Typhoon / AWD Astro / Bravada) because they're cheap, plentiful, and strong (there has been at least one full weight Sy running in the 8's on them). But, I haven't had the time or desire to figure out how to "flip" the tcase. Would probably require a new case.

Diffs are another issue. And suitability depends upon what rotation direction you have from the transfer case.

JustDreamin

I stand corrected...but in the application that I'm thinking about I would take a high pinion/reverse cut front diff, which rotates counterclockwise, looking from the pinion side, place it in the rear of the vehicle, still rotating counterclockwise. But in this orientation the vehicle would have 1 forward and 4-6 reverse gears, correct? In order to change that on would flip the high pinion diff to get 4-6 forward and 1 reverse, low pinion, and correct rotation...right? Now the new front diff presents a problem that I thought I'd figured out but as was pointed out and I confirmed I can't put a regular cut gear set in a high pinion 3rd member. This is why I ask these questions...any solutions?
Thanks,
Justin

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I found a transfer-case with a 50/50 torque split, nv225 torsen unit unique to 02-05 Range Rover so it's not lowcost or plentiful in the wrecking yards...yet but there is a path forward on the tcase.

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Some more research...Audi AWD transaxles between 1987-2005 have a 50/50 torque split via a torsen center differential, so no electronics and a favorable split. Now how to run power to a front differential from the rear output of the transaxle...frezi?
I see that Currie make a 9" high pinion case and gear set for rear axles that would be (I think) suitable for a flipped, reverse rotation front diff, neither lightweight nor locost but a possibility if one was to pursue the Lambo style drivetrain layout.

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good info