Volkswagen Vanagon 4x4 Conversion.


Some of you may have tuned into my old thread about the upgrades to my 85 Vanagon tin top.!-Long-Slow-Vanagon-Transformation

In reality my build took a turn and I skipped right to the fun/more involved part of my build, the 4x4 conversion.

Having said that, I decided to start a new thread that eliminates some of the clutter and better describes what I am doing so it's all easier to sort through.

Feel free to look at the old thread but allow me to start at the beginning.

I bought an 85 VW Vanagon tin top in Jan or Feb of 2014
It was not much to look at but it only had 80,000 miles on it and was pretty cheap.

I had plenty of ideas for what I wanted to accomplish with the van but the most important was a 4x4 conversion.
Yes 4x4 Vanagons exist but I am not super excited about the cost and reliability of parts so I wanted to come up with something else.

I wanted a more flexible suspension, a proper transfer case and a more reliable and more powerful engine.
I explored some later model or even custom independent suspension bits but the complexity and cost to make a durable overland ready platform based on this design was well beyond my means.

I wanted something simple and cost effective.
I also wanted it to use parts that are readily available and simple to replace should the need arise.
When I say readily available I mean worldwide (within reason)
The likelihood of taking this thing outside of North America myself is pretty slim but you never know where life will take you.
I figure with a little careful planning and parts choices I should be able to cover the worldly part.

With the brief background on my motivation and requirements laid out, it seemed that a solid axle swap was the obvious choice for suspension duties
Naturally, when I think of worldly, durable and functional overland rigs with solid axles, there is only one vehicle that pops into my head: The Toyota Land Cruiser.
So I set forth on a quest to acquire a set of locking FJ80 land cruiser axles.
This journey did not go quite as I had planned.
I came across some wicked cheap FJ80 axles in Pittsburgh, PA with lockers that sounded almost too good to be true.
However, I decided to make the 3 hour drive to check them out.
Turned out that it was too good to be true.
I was all set to bail when the place made me a deal that seemed pretty hard to lose out on.
"I know you drove all this way and I hate to see you leave empty handed. Would you do $100 each?"
With $200 deleted from my bank account I loaded them on the trailer.

I figured even if the housings were completely hosed I could likely salvage the lockers, axle shafts and other bits.
They would take some work but I managed to get most of what I needed.
The front diff lock actuator was corroded beyond repair.

Turned out that the rear was no better but I decided I will build air actuators for the front and rear.

I started by stripping the front housing and cutting off all the rusty old brackets to see what I could make of it.
The diff seemed functional.
Here it is de-scaled and spray-bombed.

The housing also seemed like it would work.

This is where things started to get all head spinny.
For those that do not know, the VW Vanagon is a rear engine vehicle.
This complicates the choice for a new drive-train as most engine and transmission options would come from a front engine vehicle and the trans output would be spinning the opposite direction when placed in the rear.

This means my van would end up with 1 forward gear and 4 reverse gears.

The rear engine rock crawler buggies sorted this out to some extent.
They simply (using the term loosely) flip the diffs so the tires are then rotating the correct direction.

However, when this is done it forces the pinion to drive the ring gear on the "coast" side rather than the "drive" side.
This weakens the ring gear significantly as the gears are constantly trying to drive away from each other due to the more shallow slope on which the gears are now being forced to drive.
Given the right circumstances you end up with sheared gear teeth.

The rock crawler guys overcome this by running the biggest baddest axles that they can and for the most part it works.
This usually only applies to the rear diff because the front diff in most four wheel drives are already running on the coast side.

I am in no position to run a Dana 70 or 80 or bigger in the rear so I needed to sort out a plan "B".

Right now I have two options:
1. run the FJ80 front diff in the rear flipped upside down.
2. reverse the rotation of the transmission output.

The FJ80 is one of a few vehicles that have a reverse cut front ring and pinion that is driven on the correct side of the gear when used in a front application.
If I put it in the rear, then flip it it will still be driven on the correct side of the gear.

So what do I do with the front.
Well. If I take a rear diff and mount it up front, then flip it it will also be driven on the correct side of the gear.

This is an over simplified version of what I am trying to do but that's the gist of it.

One major point here is that I would no longer be using the FJ80 rear 9.5 inch diff in the rear.
Actually I would not be using it at all.
Instead would opt to use 8" toyota diffs front and rear.
Ideally I would buy some custom housings and eventually I will but with the parts I already have, a handful of parts that I will acquire in short order and a little fabrication work I can build what I need.
I will get to the axles a little more a little later.

For now lets talk about option #2.
I am planning on running a Subaru boxer engine and its associated Subaru transmission.
In my case I am running the 4EAT auto.
There is a company that sells a kit to reverse the rotation of the 5 and 6 speed Subaru transmissions so this had me looking into how it could be done on the auto.
I need to do a little more tinkering with my transmission but I think it can be done.
This would mean that the FJ80 reverse cut diff would stay up front and the 9.5" could be run out back and everything would be running as it should be.

Ok. it's late and I should stop there for now and pick this up tomorrow but for fun here is roughly how the van will sit when it is all said and done.

It will be just high enough that I probably won't be able to get it out of the garage with tires on it.

Until next time...
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2002 LX470 expo ready
2008 Ford E350 EB V10 4x4 Sportsmobile PH top
Custom off road trailer


Engineer In Residence
What, you don't want the outrageously expensive and notoriously weak syncro drivetrain? You don't want to pay 6k for a rebuilt transmission or $500 for a front wheel bearing? You want reasonable wheel articulation and no broken CV joints? :sombrero: You are on the right track then. This is going to be one cool rig when its done. :Wow1:


Engineer In Residence
Big Syncro fan, you got my attention.

Why stop with the axles.
MMMMM reversed 1.8T... This is one of my favorite projects. The reversed subi trans is pretty tempting though.

Supposedly Flint is working on a reversed TDI engine currently. That would be a killer powerplant.

If you already haven't considered it, installing a replacement for the tiny factory tank would be a good upgrade while you are slicing and dicing the chassis. 16 gallons is just too small for anything other than a diesel powerplant.


Expedition Leader
Maybe I missed it. What kind of suspension are you going to build?
I think he is going with a straight axle coil spring setup - the Subie tranny would be reversed so its in the back (but in front of the engine).

I think he is planning on using the output shaft which normally feeds the rear diff on the subaru to go to a mid-mounted transfer case (the previously mentioned Disco xfer case) which would then feed the front and rear axles.


Maybe I missed it. What kind of suspension are you going to build?
The plan is to run a radius arm set up front and rear with plain old coil springs and shocks.
I understand that they are not the most flexible of designs but they do well enough that all of the best overlanders in the world use it.
The Discovery 2 even has it front and rear.
It will likely nearly double the suspension travel of the stock Vanagon.

I have a design that should improve flex a little.
I thought it was a novel idea until I discovered that the dodge power wagon has been using it for a couple of years now.
Essentially they just added a link with an extra bushing on the radius arm so it can move a little more when the axle twists during articulation

This is super simple and should help a fair amount with articulation.

I am running nothing more than stock front lower FJ80 radius arm bushings at all 4 locations on my radius arm design.
Once again this is because they can be found practically anywhere in the world so if you need a new one while in Morocco you could likely obtain one in short order.

I am also running softer coils and an airbag per corner so I can adjust the load capacity at will and be able to level the van out easily when parked for the night in camp mode.

This will all be coupled with some fat, stiff, disconnect-able anti-roll bars to keep it nice and flat on the street while keeping the suspension pretty soft.

Simple but effective.
That's the name of the game.
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Supposedly Flint is working on a reversed TDI engine currently. That would be a killer powerplant.

If you already haven't considered it, installing a replacement for the tiny factory tank would be a good upgrade while you are slicing and dicing the chassis. 16 gallons is just too small for anything other than a diesel powerplant.
There is a company that makes an adapter that bolts the TDI to the Subaru 5 Speeds.
With a few additions I could likely make it work with the 4EAT auto that I am using.

The plan from the get go has always been a TDI Vanagon but I already have the complete Subaru drivetrain so I have decided to use that to get it up and running and swap it to a TDI a little later.

A new gas tank is in the works as my front driveshaft location is essentially right where the factory gas tank is.
There is a lot of space above the transmission in the rear and that's where the Syncro has the tank mounted.
I have plans to put some other stuff there but if I can't squeeze a tank in under the floor somewhere I may rearrange some things and put the tank back there.
Ideally I would like about 35 gallons but I would be happy if I can cram 25 somewhere: Then I can just carry a jerry can or two if I really think I am going to need extra fuel.


Engineer In Residence
There is plenty of room between the frame rails for tanks. Filling could be a challenge, but power filling via a transfer pump is doable.

If you move the spare to the back, there is plenty of space under the front. Hmmm, definitely going to be interesting. For 35 gallons you are pretty much stuck with two tanks I think. I have seen some tank switching valves and whatnot available, so its doable.

What kind of ride height are going for? Fender lip to wheel center? Just curious.