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Options to AWD/4WD a B-Body Wagon

6546 Views 95 Replies 11 Participants Last post by  wagonmayne
This is totally serious. There's been musings about this on this forum in the past, and I remember reading about at least one frame swap that was done. I've got 3 (4?) B-body wagons in my driveway, most in reasonable shape. I'd love to convert one of them to AWD or 4WD to use as a winter warrior. So what would be viable options to achieve that goal?

Things I've considered:

- find an Astro/Safari AWD subframe and weld it in place of the front section of the B-body frame

- find a pickup/SUV frame with a similar wheelbase and re-body it

- buy a Dodge Magnum instead

The first option seems like it would retain a reasonable ride height, whereas the second one seems like it would require a significant lift. I would prefer to retain a stock-ish ride height with stock-sized wheels and tires, even if there's a change in wheel stud circle diameter involved.

The 3rd option is boring, but probably the most cost-effective.

Are there any other options I'm not thinking of?
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At this point I've probably spent as much time on this as anyone. I'm beyond serious, and I don't see myself giving up.

Here is what I can tell you:

  • The biggest obstacle, by far, is the engine cradle or cross member. It is most practical to just cut it out entirely at the frame rails, but I haven't given up hope that it might be possible to just cut/modify the bottom portion somehow. Ride height would need to be increased (big silly wheels would work).
  • The Astro AWD front track width is way too wide, so the Astro sub-frame could only be used with significant modification, which may not be worth it compared to other options
  • The simplest way to pull this off, by far, is to cut the frame rails somewhere near the A-pillar on your car and also on a GMT360 (Trailblazer, Envoy, Rainier, Ascender, 97x)... It would be pretty "basic" metal work for someone in that field, but definitely a big undertaking for the average Joe. The GMT360 front cross member is up front near the radiator support, which is perfect for this application. Swapping the entire frame is not an option, as the frame rails on the GMT360 get way too narrow rear of the A-pillar.
  • Another decent option would be to cut out the entire B cross-member and fab 4 single-bolt mounts that allow you to bolt up a sub-frame from an Audi. All of the Audis use ZF transmissions that are generally solid and easy to find in junkyards. You could use an Audi engine or use a bell housing adapter to bolt up an LS/LT. Keep in mind that the Audi and Subaru AWD systems are unique in that they position the engine ahead of the front axles, with the axles coming basically directly out of the sides of the transmission. The biggest obstacle I see here is that the B steering setup would need to go, but I don't see this being too big of a deal. With the engine moved forward, there will be plenty of space for a steering rack in the Audi location (between the engine and the firewall).
  • If you have really deep pockets, you could go this route: Homepage - Protean
In conclusion, this is absolutely 100% possible. The only reason it hasn't been done is that none of the people interested in doing it have the combination of time, motivation, skill, and money that it takes to pull it off.
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In all the time I've been reading the ISSF, never seen a non-lifted 4x4 B- or D-body.
Don't think there's enough room under our floorpans to fit a 4x4 transfer case in a way that would look 'non-lifted'.
You might have to run the front wheel driveshafts through the oil pan?
You might have to convert our frames to allow for torsion bar front springs?
I don't think the transfer case is much of an issue, even if it means banging on the floor a little bit.

Routing the axles through the oil pan may be helpful, and that's how the GMT360 does it.

The springs are a total non-issue once you convert to coil-overs or struts.
Huh... I've got Audi quattro subframes, transmissions and engines in every corner of my shop. Now you've got me pondering a TDI/quattro B-body wagon 🤣

edit: of course getting the diff ratios to match up would likely be impossible
The gear ratios would be the least of my concerns. There are many Audi diffs with different ratios to choose from. My C5 2.7T with manual trans has factory 4.11 gears, which is pretty darn close to 4.10.
Brian King's car is sweet, and also an example of just how simple this is for someone who works with metal. He literally just cut the frame rails below the A-pillar and patched in the front of a Bravada. No real engineering involved.
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Just thought I would add that one of the biggest gripes about Audi is that placing the engine ahead of the axles makes the car very front-heavy. In a wagon or Fleetwood, the rear is probably heavy enough to balance it out nicely, by comparison.
As far as the powertrain functioning, yes. But I 'd still need holes in the crossmember to accommodate the front axle shafts, proper uprights with a splined hub and the same steering geometry, relocated coil springs and shocks, and about 2" more space in front of the front axle to fit the engine
It's way cheaper and easier to cut out the cross member and install the entire Audi front end. Why bother patching all that stuff together?

And, yes, Audi power trains are very good at running entirely independent from the car they are in.
Don't even bother messing with relocating shocks and coil springs. Just use Audi struts (or even GM struts from a Trailblazer or Silverado).
It should be fairly straight forward to fab individual control arms that mount to the Fleetwood frame and the Audi spindle. (Or, fab mounts allowing you to use some or all of the Audi arms).

Why would there be any issue with fenders/body? There's plenty of space in there, especially on a Fleetwood.
For those who aren't familiar with Audi, I just figured I should add:

The older Audis, like my 2000, use a 100% mechanical AWD system, with a Torsen center diff. There is zero computer involvement to worry about, and it would integrate seamlessly with a solid rear axle.

The front end has 8 control arms and 8 ball joints (instead of A-arms, just think straight links with individual ball joints on the end). The ball joints bolt to the knuckle side-by-side. The two lower control arms bolt to the sub-frame, and the two uppers bolt to the strut towers, which are part of the unibody.

In our application, you would have to fabricate these strut towers. OR, the original B upper may work, if you were going to use a GM knuckle instead of an Audi knuckle. GM uses a fairly universal bolt pattern for hubs, so you would be able to easily choose your bolt pattern this way (including sticking with 5x5).

The Audi sub-frame, and everything attached to it, bolt to the unibody with 4 large bolts and regular-ass rubber bushing mounts.
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Can anyone confirm that the Suburban and the wagon use the same frame? Sure would simplify things if it did.
They absolutely do not.
I've refinished a suburban frame from scratch before. There's zero similarity there. Especially under the body.
The only similarity is that they are both frames.
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BTW @GoremanX I realized you were likely referring to the inner fenders. Sometimes I forget about them because my car still doesn't have any. Or an engine, for that matter.
🤣 It's easy to forget what cars are made of
Well, in this case, it's more that I forgot to address potential self-imposed limitations.

AWD means enough to me that I am willing to ditch my inner fenders, cross member, core support, etc. They are afterthoughts for me.

Those of you who are trying to make this happen within your own mental construct will have more to sort out.
Sure. This is like looking at a road map and mapping out different routes. There are a lot of different ways to get from point A to point B, and the practicality of them will vary from person to person based on individual skill set and resources.
He sectioned in a trailblazer ss frame
No. He sectioned in a Bravada front frame, which is basically identical to the Cutlass frame aside from having the crossmember moved out of the way of the axles.

What Brian did is much easier than what you are talking about.

You would not be the first to put a truck frame under a B-body, as there are pics on the net. There is a lot more to it than wheelbase.

I've pondered swapping in a GMT360 (Trailblazer) frame, but the biggest issue is that the frame rails are in the wrong location.

If you actually want to do AWD, the easiest and cheapest way is to just cut out the engine cradle entirely. Then you weld in a new crossmember up ahead of the engine to maintain rigidity. Then you can piece together the AWD parts from whatever GM vehicle you want that has a 4L60E with AWD/4WD.

There is no easier or cheaper way to do it.
Truth... the frame contours the body very closely, and the floor pan sits deep in the frame. I can't imagine a truck frame maintaining that at all. I solved the issue by buying a 1999 K1500 Suburban and dropping it a couple inches. Almost the same overall length, AWD/4X4, and much safer towing. It's a perfect working vehicle to complement my cruising/road trip Roadmaster
Yeah, another issue with the truck frame is there are multiple crossmembers that would be in the way of the floorpan.
If you actually want to do AWD, the easiest and cheapest way is to just cut out the engine cradle entirely. Then you weld in a new crossmember up ahead of the engine to maintain rigidity. Then you can piece together the AWD parts from whatever GM vehicle you want that has a 4L60E with AWD/4WD.

There is no easier or cheaper way to do it.
Why go to all the trouble of a frame swap? Couldn't you just get the transfer case off an awd astrovan? They used a 4L60e...
And where do you suggest running the front axles? Or attaching the front differential?
You have to fab all the mounts.

The parts are out there from 11 different vehicles, but nobody has been serious enough so far.
If you want something like that, buy an Allroad.
Let's be real an Arctic Master is way cooler than an Allroad
Yeah but the fact that it doesn't exist puts it at a big performance disadvantage.
it's idiotic that it doesn't say anywhere in that text that it's just a render and not an actual thing.

I have an Ur-allroad. I prefer my Roadmaster
Which one is faster in the snow?
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