Turning a Transverse motor for AWD?

Hello everyone, not sure if this is where to post but I've been brainstorming and AWD build for a project car in the garage. Now I'm wondering if this has ever been done or if it is even possible.

Could you turn a transverse motor and trans 90° and run each output from the trans to a differential for AWD? Just curious if this idea has ever been implemented before in a car. Basically the axles would now become the driveshafts that lead to the front and rear differentials, then out to all 4. heels for symmetric All wheel drive.

Also if this is the right section to ask questions, how do gear ratios work in transverse awd vehicles? Most are assisted awd, since it doesn't engage all the time, is there a big issie with matching ratios? Also do the awd transfer cases have ratios to them? As in a dodge stealth or Chevrolet Equinox transfer case? or is this just a simple 1:1 ratio input/output?

If this is in the wrong spot just let me know, otherwise thanks for any input, just trying to learn more about some awd systems

http://www.allpar.com/model/jeep/jj.html

Doesn't go into much detail but sounds like what you're talking about.

The problem there I think you'll find is gearing. Probably fine for a rock crawler, otherwise you'd need front and rear diffs with as close a ratio to 1:1 as possible.

http://www.pirate4x4.com/forum/general-4x4-discussion/562853-project-lo-budget-pimpin.html

http://www.pirate4x4.com/forum/general-4x4-discussion/633445-honda-powered-kid-buggy.html

Run_Away is right on the money with gearing. Highway speeds would be tough, but it's gotten pretty popular in the Rockcrawling community. The TV show Xtreme 4x4 did a build based on Rock Ape's Lo Budget Pimpin buggie.

• Lee

I saw a rock crawler on one of the Spike TV car shows some years ago where they did this with a Honda engine and transaxle turned sideways, but as mentioned the gearing may be tricky for a street car.

This is it.

Rhino offroad industries.

Roger

Pretty sure the iceracing R1-powered Geo runs something along these lines.

4t60 gearing explained

check that out. it has a chart that shows the 12 different final drives you could make with a 4t60 gm transmission.

if you set the trans up to be a 2.39 final drive and get your hands on a couple 8.5 chevy axles, you may be able to source some 2.29 cadillac gears and put you in the 4.7x final drive range. still quite high but overdrive helps.

If you can work with your tire sizing, you could get around a 3800 RPM @ 75 MPH with a 31"-ish tire with a scenario like Patgizz mentioned above.

• Lee

It. Could. Work!

Wow, this is a terrific forum here! I've been reading everything I can on here and I've learned quite a bit already! I see about the 1:1 ratio in the diffs and tire size couldn't be modified but still neat to see it be done in those rock crawlers!

Now if you people could help me understand another item I'm confused about...the Awd systems that use transverse motors with a PTO/PTU unit, is there a ratio for those units? In a GM car/SUV, they use the same trans with or without the PTO so that makes me think the PTO unit spins off the speed of the axles, and the different sets of gears help with the speed of the driveshaft to the rear? And since they are assisted awd, does the rear end have special gearing or a freewheel type differential to deal with the free spinning when not engaged?

Basically I have a getrag f23 fwd 5 speed transmission that I have been trying to make awd in my mind and this seems the only place where I can ask questions without being told it is impossible. My main goal here is to learn anyways so thank you all so far!

Wait, what?

PTO usually refers to an attachment for farm implements. Do you mean the front output shaft? This would spin the same speed as the other output shaft, unless we're talking about mega $$$$ custom rock crawling gearboxes.

What do you mean by "assisted" AWD?

Generally, AWD cars have a center differential to allow for slip between front and rear axles, as well as a differential in each axle to allow for slip between each wheel.

i was thinking that the other day at the pull a part while removing seats from an all wheel drive buick rendezvous. i'm tempted to go back and look at things, disconnect a driveshaft and examine the rear diff. i want to go a different direction one day though and pick up a cheap rendezvous AWD with a bad trans(they cost like 3 grand used on car-part.com so vehicles with bad trans sell cheap) and yank all that crap out and make it RWD, if the diff can take it or if one could swap in the center section from another rwd vehicle.

That is a picture of a Pontiac aztek awd transmission. The ptu unit bolts to the pass. side of the trans and there is an output for the pass. Axle on the other side of ptu. This is how the awd system is handled on most GM part time awd systems. But it must be powered by the same speed as the axles, which means the gears help with the speed of the driveshaft to the rear, correct?

Either that weird little turnaround box increases the speed of the output to the rear roughly 4x and the rear diff then drops it rougly 4x, or the speed going to the rear is the same and the rear diff is a 1:1 gear ratio (unlikely).

That's what I imagine, meaning I could adapt one of these PTU units to my f23 and run AWD theoretically.... I think I will just need to get my hands on one and spin it to see the ratio within the gearbox. It seems to be a completely separate item from the transmission which makes me think it could be made to work with any transmission. Ideally I would like a solid rear instead of part time awd and a center differential like most AWD systems use.

You can see the planetary gears in the drawing. The shaft that the axle bolts to on that side probably spins it. Then a chain (or shaft) back and a 90° turn. So the gear ratio has 3 spots that it could change.