audi 4wd to 2wd conversion

[John W]

Is it possible to convert a 4wd box to 2wd, or is it simply too costly to do ?

If I wanted to do this, what would I need to replace on the box ?

Thanks,
John.

 

[Mark Worthington]

I looked into doint this and it just isn't cost effective. You can re-use the case, the input shaft and some of the gears, but you need a new end shield (the tail piece), gearbox cover (the cast iron piece between the end shield and the case), output shaft, and pinion gear set. The cost you will pay Audi for these parts will approach that of a new transaxle.

Alternatively, you could source a quattro box, cut off and weld up the rear output shaft (don't recall the technical term for this piece right now) to the hollow output shaft, and fabricate a new end shield to close up the back of the transaxle. Since this configuration would likely have some weird harmonics that weren't considered in the original design of the transaxle, it might not last that long but it would be interesting.

 

[John W]

Hi Mark,

I have a 4wd RS4 box which is currently one of the strongest boxes they make.

It seems the easist way to make it 2wd is to weld up the torsen diff contained in the tail section. This is a common mod for racing Audi's apparently.
What I'm looking to do though is change the tail casting for a 2wd one, and somehow directly connect the lay shaft to the drive shaft (which runs up the inside of the hollow lay shaft).
On 2wd boxes the lay shaft is also the drive shaft,
so another option seems to be to change this shaft out.
The shaft diameter is meant to be the same diameter, so the gears are interchangeable.

Btw, the central casting (you call it the gearbox cover) is the same for both 2wd & 4wd. I checked the Audi part numbers.

A good friend works for Audi as a technician, so I'm hoping to get any parts required at trade prices /ubbthreads/images/graemlins/smile.gif

Thanks for the response. I'll let you know how I get on.
If its too much hassle I'll just buy a 2wd box. I'm also checking out the 01X box details posted on the other thread.

Cheers,
John.

 

[Mark Worthington]

[ QUOTE ]
Hi Mark,

I have a 4wd RS4 box which is currently one of the strongest boxes they make.

It seems the easist way to make it 2wd is to weld up the torsen diff contained in the tail section. This is a common mod for racing Audi's apparently.
What I'm looking to do though is change the tail casting for a 2wd one, and somehow directly connect the lay shaft to the drive shaft (which runs up the inside of the hollow lay shaft).
On 2wd boxes the lay shaft is also the drive shaft,
so another option seems to be to change this shaft out.
The shaft diameter is meant to be the same diameter, so the gears are interchangeable.

Btw, the central casting (you call it the gearbox cover) is the same for both 2wd & 4wd. I checked the Audi part numbers.

A good friend works for Audi as a technician, so I'm hoping to get any parts required at trade prices /ubbthreads/images/graemlins/smile.gif


[/ QUOTE ]

I can understand why the Audi guys would weld up the center Torsen, because it would effectively give them a 50-50 front-rear split. But doing so for a 2WD box would mean you would have to lug the heavy (man, it is really heavy) center Torsen around with you. The way the Quattro box is set up the rear output shaft runs concentrically inside the front output shaft. All you would have to do would be to cut them both off (in front of the center Torsen), weld them together, fit a 2WD or custom fabricated end shield, and hope for the best. When I researched the gearbox covers for 2WD and AWD 01E boxes I thought I observed different part numbers for the gearbox covers. You can check the spreadsheet I posted here a while ago (on the GT40 library sub-forum)...I started to build a worksheet that compared 2WD and AWD part numbers.

When I checked with Audi just the 2WD output shaft was something like 900 GBP. So I think the best way to approach this is to experiment by welding up a Quattro 6-speed or by sourcing a 2WD 01E. The 2WD 6-speed boxes show up fairly regularly on Ebay.de and go for 500-800 Euros.