Hey guys anyone successfully convert our cars to awd, I was doing some research and saw that an F46 transfer case from an 09 Saab 9.3 xwd turbo should fit the F23 trans but what about the rear end? I was thinking a 90s' Corvett rear suspension with the Dana 44 rear with 3.92 gears would match pretty close with the 3.91 fdr of the F23 trans, any thoughts?

there is no close 'enough' with awd, just pull the trans transfer case and rear suspension out of the same car to keep the gearing the same unless you plan on changing one of those parts often because they'll break.



I miss my Cavalier, even if it made 100 hp on a cold day and had more suspension then it deserved.

Dale Young wrote:Hey guys anyone successfully convert our cars to awd, I was doing some research and saw that an F46 transfer case from an 09 Saab 9.3 xwd turbo should fit the F23 trans but what about the rear end? I was thinking a 90s' Corvett rear suspension with the Dana 44 rear with 3.92 gears would match pretty close with the 3.91 fdr of the F23 trans, any thoughts?

That would probably work fine, it's common for the gearing to be slightly off like that, a lot of vehicles came from the factory that way. 2% difference is acceptable. A lot of vehicles cam with 3.50 and 355s. Other came with 4.10 and 4.11s. It all depended on axle choices.




On the inside my car looks like a fighter jet.

I would try to stick to the same FDR, but that close should work.



PRND321 Till I DIE
Old Motor: 160whp & 152ft/lbs, 1/4 Mile 15.4 @88.2
M45 + LD9 + 4T40-E, GO GO GO

The thing about AWD setups on FWD platforms, which is the case on the F46, is that the FDR is controlled by the transmission, and the transfer case and rear end are 1:1 ratio. Read up in the 3rd gen AWD Eco thread. I've provided a lot of information in there. I would recommend if you're going to try it, to get the F40 and F46 transmission from the same car, and look at getting the rear out of a Saab a few years older without the electronic rear end. Also, the F35 will not have the secondary drive output for the transfer case. The F46 a concentric setup, with the passenger side axle drive passing through the transfer case into the differential, and the differential having an outer spline drive specifically for the rear output of the transfer case.

i had thought about the 60 degree v6 vehicles i.e. buick rendevous for donors but i hate auto trans.

My Z is Slow (Mike) wrote:i had thought about the 60 degree v6 vehicles i.e. buick rendevous for donors but i hate auto trans.

You can do it with a 60° V6 and manual. There's a version of the AWD F40 tranny that mates to the 2.8 or 3.6 motors. You can also use the F40 from a 3.5 or 3.9 if you want to swap over the AWD diff and output shaft.

Technically the rear diff would have to match the ratio of the transfer case. From what I’ve seen, the transfer case and rear diff aren’t 1:1 in a literal sense in fwd based awd systems, they have matching ratios which equal a 1:1 or near 1:1 ratio.

strat81 wrote:Technically the rear diff would have to match the ratio of the transfer case. From what I’ve seen, the transfer case and rear diff aren’t 1:1 in a literal sense in fwd based awd systems, they have matching ratios which equal a 1:1 or near 1:1 ratio.

You're correct. I'm not actually sure of what the ratios are, but I know that there are a number of variations of the rear diff that match the F46 transfer case, and the one to use in this application would be the LSD one, not the e-LSD that has the computer controlled slip.

I haven’t had any luck finding the ratios either... from what I’ve seen though, the Saab xwd guys seem to have issues with the rear diffs. I’d prefer to find something from another vehicle that has aftermarket support for an lsd IF you can find something with a similar ratio to the transfer case.

Is the Saab transfer case electronically controlled as well? Wasn’t sure if it was a fwd until awd is needed type of setup or if it’s full time.

The F46 is not electronically controlled, from what I have seen. I have a blowout diagram somewhere, and there are no sensors or any kind of connection that I saw on it. I believe it's full time, but the Haldex e-LSD is controlled by steering input.

I know this is forever old, but so is most of this site these days.

Little help on that rear diff situation though, the IRS from a Subaru ('00-04 or so) has a similar setup as the N-body IRS. Would make bolting in easier. Diff options are what ever Subi has, or upgrade to a R200 diff from Nissan.


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