Rear end upgrade options?
Thread Starter
Drifting
Joined: Oct 2012
Posts: 1,424
Likes: 21
From: Austin TX
Rear end upgrade options?
Checking into upgrading the anemic 2.56 factory diff in my 2008 A6 base coupe. Compared a 3.42 diff out of a 2007 M6 coupe, and it has an opening for a smaller T-56 transmission shaft so it won't work. What factory diffs will fit the larger 6L80E transmission shaft? The 2.73 "performance option" diff,I would imagine, but are there any steeper than 2.73 gear option diffs that will mate right up?
If not, where is the best source for a set of steeper gears that will fit in my original diff?
If not, where is the best source for a set of steeper gears that will fit in my original diff?
Race Director
Joined: Sep 2007
Posts: 16,557
Likes: 2,106
From: Peoria/Phoenix AZ
C6 of Year Finalist (performance mods) 2019
A 3.42 Z06 dif will fit, but if you're looking for bigger gains, go with a higher stall converter. The 3.42 will give you a max of .1 seconds in the 1/4. Even a real street friendly 3200 stall can double that for about half the price.
Thread Starter
Drifting
Joined: Oct 2012
Posts: 1,424
Likes: 21
From: Austin TX
Guess I need to look for a ZO6 diff, because the 3.42 diff that we compared was for a smaller transmission shaft. If what you say is correct, the one I looked at must have been from a base coupe with manual trans. I don't intend to go to the dealer and plunk down rape money for a brand new one. Idea is to find a nice used unit that checks out.
Race Director
Joined: Sep 2007
Posts: 16,557
Likes: 2,106
From: Peoria/Phoenix AZ
C6 of Year Finalist (performance mods) 2019
Thanks, but already have a Circle D triple disk 3200 stall.
Guess I need to look for a ZO6 diff, because the 3.42 diff that we compared was for a smaller transmission shaft. If what you say is correct, the one I looked at must have been from a base coupe with manual trans. I don't intend to go to the dealer and plunk down rape money for a brand new one. Idea is to find a nice used unit that checks out.
Guess I need to look for a ZO6 diff, because the 3.42 diff that we compared was for a smaller transmission shaft. If what you say is correct, the one I looked at must have been from a base coupe with manual trans. I don't intend to go to the dealer and plunk down rape money for a brand new one. Idea is to find a nice used unit that checks out.
Thread Starter
Drifting
Joined: Oct 2012
Posts: 1,424
Likes: 21
From: Austin TX
Thanks. I "know" subfloor and have talked to him in the past. I'll do the search.
That's the thing about asking for advice on forums - and I appreciate yours - the advisors always want to go off on a tangent - sometimes that's all they do rather than just answer the question. At least you answered the question too. But about the tangent: the car is not remaining NA for long. I'm only partway through the build. It's also not going to be a track-only car. It will see street use. At least that's the idea now.
That's the thing about asking for advice on forums - and I appreciate yours - the advisors always want to go off on a tangent - sometimes that's all they do rather than just answer the question. At least you answered the question too. But about the tangent: the car is not remaining NA for long. I'm only partway through the build. It's also not going to be a track-only car. It will see street use. At least that's the idea now.
