After the holidays ill be looking for a 3.42 diff to replace the 2.73. Question is what is the difference between the Z06 diff and a non-Z diff? Also will the diff from a manual fit my A4 without problems? I know i'll have to get the shift points changed but will actual fitment work? Thanks. Also if anyone knows a good place to get one, I'd appreciate it. I've looked in the parts section and there havent been any around lately or they are sold already.
Thanks again and happy holidays.

 

The z06 diff is shot peened for greater strength. Not sure if there is any other difference.

Yes, a 3.42 from a manual car will work. There is just an adapter plate you will have to take off your old one and attach to the new one. Other than that, it will work just fine. My 3.42 that I got installed in my auto is from a manual car.

 

I swapped the 3.42 from my '02 M6 C5 to my wife's '02 A4 C5 a few years back (put 4.10's in my M6). You need to pop off the adapter plate from the front of your 2.73 diff and press it onto the 3.42 diff. I bought new seals for the tranny interface when I did the swap. I also put in a high stall torque converter to complement the lower gearing. I did my own shift point and pressure changes using EFI Live.

You will love the improvement the 3.42's give the car. As so many have said here, "Shoulda' come from the factory like this."

Here's the thread I posted on my installation.

http://forums.corvetteforum.com/c5-g...mega-pics.html

 

C5 Corvette Differentials

We offer many options for a C5 Differential, depending on application and expected use.

Feel free to give me a call with any questions,
Tom 1-800-862-9632 ext 240.

 

^ I'm looking to picking up some 3.90's sometime next year. It looks like you guys have some decent products. I'll look into it when the time is right.

 

How much did it cost for the install and did you have new seals put in?

 

It takes all of 2 hours to do it at home if you have 2 jacks and stands.

You want to block your front tires. Next you want to jack up your rear end as high as you can. You will need to take off your TT plate cover. Yes this also means taking off your X or H pipe. You will need to remove your rear tires and rear break caliper off your rotors. You will need to disengage all your electronic connections to your transmission and rear diff. You will also want to loosen the shock in the rear.

There are 3 bolts holding your transmission to your differential those need to be removed. Your hand break connectors will also need to be removed and placed out of the way. You also want to make sure all your break lines are not in the way.

Once this is done you will place a jack with a wide base on your rear diff cradle, and one on your transmission, this is because you will begging to unscrew the 4 screws that hold the cradle to the body. This will have to be slow because you will need to disengage some break lines and your rear shocks and drive shafts. Once the cradle is out of the way the diff/tranny and is being held up by the second jack. IF YOU DO NOT TAKE OUT YOUR TT PLATE COVER YOU ARE GOING TO HAVE A BAD DAY. Now slowly lower the tranny diff assembly. One this is done and everything is disconnected you will easily be able to slide the rear diff off and. Make sure as not to hurt the rear diff plate adapter that comes for the A4’s and along with the plate the adapter plate seal. Me you buy new seals.

Once that is done slide the new diff in plate with the adapter plate and seal and jack up to correct position and work backwards. Also make sure to drain the fluid out of the diff before you start.

If I forgot something its been 2 years sine I did mine.

Good luck

 

You forgot disconnecting the air bridge..Not lowering it too much so the motor is against the firewall and I doubt anybody can do it start to finish in 2 hours!

 

I bought it from forum member near me who had upgraded his diff. He was kind enough to install it for me. It did not get new seals, but it's never a bad idea to do it considering how many you hear of on here leaking.

 

You will have no issues using a 3.42 Z06 rear in your 2.73 car. A lot of us have done it. I can say though that I was expecting a little more than I got. Everyone said it's like a new car and I think its a nice upgrade but not a new car. Although spinning the tires with my A4 is a lot easier now.

 

You will have to reprogram your shift points up and down.

 

if you don't you'll be bouncing all over that rev limiter and the tranny will have a hard time shifting.

 

This is correct -

You will need the tune to be changed to 3.42 ratio - this actually can be done with a handheld tunner if you already have one - or if the shop that will do the work has a tuner it can change the setting in the PCM

Here is a chart with the ratio differences in RPM and MPH:


and web site to have fun with too:
http://mysite.verizon.net/foofoo2/c6/

If you have extra questions you can call or PM too

Thanks,Matt 661-406-7516

 

shop i talk to said it was a 10 hour job in the GM book???? you guys make it sound easy, might just have to try it myself....

 

How do you think they make money most mechanics I know work on a flat rate they get no OT they only get paid for the job hours they work a week. If they are not wrenching they are not getting paid.