This applies to just about any Audi quattro manual transmission made in the past (016,01E,01A,01X,0A2 etc). Thanks Scotty for the verification. I've never seen a FWD transmission in person (so diagrams are my only references), but I've seen threads on other boards of people putting together kit cars and wanting to de-AWD transmissions to use in their kit cars being warned that transmission failure is most likely due to the hollow shaft not being able to support all of the power going through it.
So, could you make an AWD transmission FWD? Maybe... assuming the main transmission casing is the same between the two... however you would still need to change to the soild FWD output shaft (I doubt the AWD hollow shaft would hold up for very long with all of the power traveling through it to a welded up center differential and back up to the front differential) and the FWD transmission back plate. You may or may not also need different bearings and races as well when changing between the two. So even if it could be done it would probably be 1. cheaper and 2. less of a headache to just buy a FWD transmission.
To understand why you first need to know how the transmissions function. Both have the upper input shaft and a lower output shaft. The FWD transmission simply has a solid output shaft that runs from the backplate of the FWD transmission housing to the front of the transmission (where the front differential is). The output shaft has the final drive pinion on the front of it and it drives the front differential which drives the front wheels of the car.
The new gearbox is designed to handle 295 lb.-ft. (400 Nm) of torque and is expected to yield fuel-efficiency gains “in the double-digits,” compared with a conventional 6-speed FWD transmission, says Michael Paul, ZF management board member.