xBoostx

I have '11 grand sport a6 with 2.73 diff gear and will like to find out if the 3.42 diff gears from Z06 or Z51 will be able to couple with the a6 diff, and if so what it takes, I called some known trannie dealer and they asked $1,999 to change the gears, is this really necessary thanks in advance for your input, David.

timd38

Sounds about right. You have to R&R the diff (5 hours or so), setup the ring and pinion (3 hours or so), plus about $1,000 in parts.

xBoostx

Well really is in a different state so they are not removing and re installing I which this was the case.

I do like to find out if is possible to swap diffs from stick to auto among c6 can anybody chime in as I'm new to corvettes thanks again.

timd38

I went from 3:42 to 3:73,so I have lived through a diff gear change.

dbratten

Swap the entire differential. The C6 Z06 diff w/3.42 will bolt up to the A6 trans. If you can sell your 2.73 diff it makes it fairly cheap. Do a search as there is a bracket needed to mount the Z06 diff. Many have made the swap.

Personally, unless you are drag racing, I feel the 3.46 gears are too much. I went from 2.46 to 3.15 and that is close to too much. I made the change for autox use. 1st gear is barely usable and with the 3.46 gears it would never need to be used.

--Dan

xBoostx

Great so you changed the gears did you buy the ring and pinion and if so where will love to change my own thanks.

xBoostx

3.42 will be perfect off the hole with D/Radials and wreck havoc on the street as all that's needed is traction, can you please elaborate more on the bracket needed, stupid question is it after market or comes in the ZO6 thanks.

dev1360

Z06 diff is a direct bolton for you. You may have to block off the speed sensor hole. It's a 30 spline pinion with a 9" ring gear. Same as your diff.

subfloor@centurytrans

A Z06 differential will fit but not one from a regular 6 speed car as the spline count is different.

The car is fine on the street as first gear is more than still useable and it also doesn't need a special bracket to install.

xBoostx

Halleluiah thanks guys for sharing and for your input and knowledge you truly validate the purpose of this great forum, next is I need a C6 ZO6 diff with 3.42 gears (is official) let me know if you know some one selling one I'll be interested thanks again dev1360 and subfloor.

My car been auto will really benefit from 3.42 diff gears my 1st should become 13 + to 1 gear reduction and where I want it.

One more question, is there a particular C6 ZO6 diff I should avoid or are they all ok?

dev1360

I'd always say to get the newest one you can, but they should all be the same.

xBoostx

Great thank you...

CI GS

I just did a Z06 diff swap on my '13 A6 GS (many thanks to subfloor for his able guidance) and I couldn't be happier with the 3.42 gears. It's a whole different car, although I did a FTI 3600 stall at the same time, which does make 1st and second gear practically useless with the stock runflats now. It can't hook at all now in 1st and 2nd and I end up leaving a big cloud of tire smoke every time I launch it.
As subfloor said, it's a straight bolt in and there is no bracket needed. You will need to change the Z06 oil pump/cover and plug the drain and fill holes. Zip has a neat kit with everything you need for that (if you don't want to pull the parts from your stock diff):
http://www.zip-corvette.com/catalog/...category/8288/
The Z06 diff does have a sensor on the top that your car won't have a wire to connect to, but I just left that as is.
However, unless you get a good deal on a used Z06 diff, perhaps the more economical route would be to get an A6 diff from Chuck @ CoW. He quoted me a really good price (cheaper than RPMs cheapest diff) on an A6 diff with the 3.42 gears. I went with the Z06 because Im overseas and it was just too much trouble and costly to bother with returning the core.
Good luck with whichever route you may go.

timd38

I bought all the special tools from a closed Chevy dealer. The issue is getting all the shims you need. I ended up trading the tools to a shop for doing the swap.

Good luck!

xBoostx

Hey CI thanks for taking your time man do appreciate that, I must say I seen it coming with gears and inappropriate tires = no traction.

What I did is and I call it the multiplier is a 3 way improvement in the case as my car with auto tranie is Tires first then torque converter and gears, already have the tires they are 345 30 19 Nitto nto5R drag radials then already order the converter is 3,400 stall p a s from Yank I should be getting it by Feb 5th so I'm now after the diff so I can put those tires to good use, then new Nittos d/r look really impressive and can't get no tire spin at all (so far).

CI GS

No worries man. Those 345 NT05Rs are probably what I'm going to put on the car soon. How do they handle in the rain?
Your car will be a beast with the PAS 3400 and 3.42s. The only reason I did the diff and the converter at the same time is because it's a lot of work to pull the rear cradle to do either and I thought, what the hell, might as well kill two birds with one stone.
Good luck and let us know how it goes.

timd38

The labor bill is a killer and if you do it your self, the amount of time it takes is a killer. If you are thinking of doing anything else, do it all at one time.

dev1360

I've had the driveline out of my car a few times. When I pulled my diff, I did it on my back in the garage. Had the diff out in an hour from when I put the car on stands.

Have a good trans jack and a tall jack stand to hold up the trans.

subfloor@centurytrans

Yep, swapping just the diff takes under three hours and swapping the transmission and/or converter takes an additional two hours.

timd38

So my 5 hours in post 2 was pretty darn close!