Hi,

Are there any technical transmission experts out there?

I am building a kit car and want to use the A8 powertrain mounted in a mid engine configuration. The A8 3.7 came as a 2wd, but all of the 4.2s were 4wd. I would strongly prefer to use a 4.2 engine. So, if I fitted a 4.2 along with its 4wd transmission, could I simply disconnect the rear wheel drive output shaft and just use the front wheel drive outputs (now driving the rear wheels of my kit car)?

Specific questions:

1) Is this possible

2) Would it damage the transmission

3) Would I need to open up the transmission and weld up the front/rear diff unit

Any help or advice would be really welcome.

Thanks!

 

I think you would lose power because of the back wheels not bein hooked up not sure on that though

 

1 yes
2 maybe, dipends the way you do it
3 open tranny ye, weld only central diff

now question for you, Why? just swap the engine.

 

Let me start by saying that the 3.7 and 4.2 use the same external block. At least as far as i know. You dont see many 3.7's. Therefore the 3.7 trans should bolt up to the 4.2 engine.

1. Its definatly possible.
2. Transfering all power thru the front differential may cause some proplems as it was designed to handle only half the power.
3. Thats the tricky part. The center differential is the most rearward part of the trans. Right before it is a gear and a transfer shaft that transmits power to the front differential. I dont think you would lose any power to the center differential as it would just freewheel with no output to the driveshaft for the rear differential. Couldnt really say for sure thou.

 

there are several companies that specialize in custom trannys not to mention the number of companies that use the audi engines (in particular the 4.2L 5v V8) i.e. Spyker & YES!
There's also a company in Indiana that builds (or outfits its...) 6 & 7 speed sequential trans for kit cars. Can't remember the name came across it one night during a google binge.