I am going to do the 3.42 gears soon. I have read a couple of threads about the ZO6 rear end and how it is a direct replacement for my 08 C6 A6. Is this true and does anyone have any experience doing this swap? Is this something I can do in my driveway?

 

I dont have experience with the swap, but from what ive read the thing is supposed to swap in easily (relatively speaking). then I saw something from rpm transmission that said they had to replace some shaft. in any case, the other modification that tends to always be done is blocking off the ports for the diff cooler. the cooler blockoff kits are cheap, but if you could run the cooler, imo it would be a good investment for reliability.

look up rpm transmission and they should be able to give you all the information you need - they are the highest regarded company when it comes to c6 diff/trans mods.

good luck!

 

Yes it is true (for the A6 cars that is, not the A4s or the manuals as they require much more) but I don't personally have any experience with it. I believe that there are any shaft changes needed and that it might only require a certain trans/rear mount part change (there might be a couple of options there as well) in order to work.




It depends on your skill level. If you've rebuilt a motor before then yes...if all you've ever done is an oil change then no. It can be done in the driveway but a lift would make it MUCH easier.

 

The Z06 transmission has a larger output shaft and different spline count then the transmissions used in the base C6. The Z06 differential has a larger ring gear and the pinion gear is designed to fit the larger transmission output shaft, so it's not a direct replacement.

I don't know if the aftermarket makes conversion parts need for the switchover. Several companies do install automatic transmissions into Z06's but I'm under the impression that they use a beefed up differential that is used in the base C6, not the Z06's differential. BUT, I'm not positive. It's difficult to keep up with what's happening with the aftermarket guys.

 

Well I hope JoesC5 is wrong... can anybody that has actually done this modification confirm or deny the fact that it is a direct replacement?

No disrespect JoesC5, just would like another opinion... right now it's 2 to 1 in favor of the direct swap.

 

That is true when attempting to put a C6 Z06 rear in a manual (or any 2005) C6 LS2/LS3, but it is not true for the 2006 and up 6L80/A6 automatic equipped cars. It is almost a bolt in replacement for the A6 cars.

 

To the OP, not to get off track but did you consider the 3.15 gears before you made your decision on the 3.42's? I'm only asking as that is where I'm at now. I do have the E-Force SC so I have been leaning more toward the 3.15 gears.

 

with the 315s youre supposed to get a bit more top end acceleration vs the 342s. supposedly the 342 gets just as slow as the 256 up top (due to getting into 6th gear sooner).

I think the best for low and top end acceleration will be somewhere in between the 315 and 342.

with the power a supercharger makes, Id go with the 315, but the 342 will also work well. with either gear, your top speed should be somewhere around 200 mph

 

Chuck Cow says 3.42's are the way to go. I believe him. I just got his whole tune package with Cow booster and am eager to see how that works but 3.42's are definitely in my future.

 

Call me if you can't find a used C6 ZO6 diff cheaper.

The C6Z has a large (30ish) spline and so does the A6 car from 06 to present.

The C6Z diff will definitely fit, but there is slightly less output shaft spline in

the pinion as the pinion sits 1 inch further back as the Z's larger ring gear makes

the C6 ZO6 about 1 inch longer.....(so the pinion is 1 inch further back)

But, it DOES WORK FINE.

We have done MANY, MANY supercharged 3.42 A6's and everyone loves them....

The 3.15s are weaker and for a street car I would go 3.42 without question.

3.42s also offer a better ratio to help take the load off of the stock internals of the A6.

Use a 3.42 with MY tune and a stock trans should last a good long time.

PUSH too much power thru a 2 series (2.73 / 2.56) rear end and then wonder to yourself

why you busted up the poor A6 trans....

Its a great trans and will hold up fine if you gear it correctly....

Think of the car like a children's SEA-SAW...

Fat kid on one side and skinny on the other....NOBODY is gonna have fun....

TOO MUCH UP FRONT ruins the ride.

Balance the SEA-SAW out with two kids of similar weight and it's a lot of fun.

BIG power up front does not make the car faster in every sense....

Less power up front and a more favorable ratio out back makes for a snappy ride

and then it's "BALANCED" and you're less likely to break stuff....

That's my FREE advice for the day.
Chuck CoW

 

I stand corrected. Can anyone explain why it costs so much to put an A6 into a Z06, if it's basically a transmission swap and clutch to converter, dump the clutch pedal, add the auto shifter and some rewiring? I've never asked for a quote on getting my Z06 converted, but I understand it's very expensive. RPM's site dosen't give any info on the conversion other then a few photos and some 6-7 word captions.

 

Im going with 3.42's,but having Tracy (Bat Car) at RevXtream install a gear set in my case.

 

The issue is......The mechanical aspect of it is relatively straight forward.....

The programming is complicated and varies from year to year....

You can't just attach the wires and think it's gonna drive....

It's something I'd have to do for you here.....It's a PITA. Trust me.

Most guys bail and go for the 4 speed, but I think that's silly since the A6 is so amazing.

Don't try this at home.
Chuck CoW