changing rearends
Team Owner
Joined: Dec 1999
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if you have a good case I have the internals of my 3:42's...top of the case cracked where the bolt goes thru..everything else is 
Team Owner
Joined: Apr 2001
Posts: 54,204
Likes: 180
From: S.W. Ohio. . . . . . NRA Life Member
can i just change the gears or do i have to change the rearend
It can be done though , but it takes a custom made part that is not available to the DIY'er. Right now, only DTE can swap-in bigger gears into a 2 series case.
Even with a 3 series case, internal gear swapping is best left to the professional. The C5 Getrag carrier (diff) is unique.
http://mikemercury.home.att.net/342.htm
Pro
Joined: Oct 2003
Posts: 618
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From: Putting a 50¢ sticker of the U.S. Flag on a $50,000 import does not make one a patriot.
I agree.
Check out DTE. They will sell you a lower gear professionally installed in a carrier. A complete unit. And they will take your 2.73's for a core, they are the only ones who take 2.73 differential cores. They have a special process that Tim mentioned earlier that allows them to rebuild the 2 series carriers with 3 and 4 series gears.
Don't forget to reprogram you PCM after the gear install, or else you'll be bouncing off the limiter at WOT.
My first C5 had 2.73's, I installed 3.42's. I liked the 3.42's, they are without a doubt the most popular gear choice for the A4.
My current C5 has 3.15's, and I just ordered 3.73's. Fun, fun, fun. I debated 3.90's but I thought they were a little too tall.
On a side note. 3.73's are only available from Getrag right now(the OE supplier to GM). Motive Gear, who makes the 3.73 ring and pinion for rebuilding differentials, has had some troubles with the 3.73's. So DTE has not built one in a while.
Here is a good gear calculator http://www.kabamus.com/garage/gears.html
Have Fun,
AZC5
PS. Sorry for the long winded post, I had too much coffee this morning!
Check out DTE. They will sell you a lower gear professionally installed in a carrier. A complete unit. And they will take your 2.73's for a core, they are the only ones who take 2.73 differential cores. They have a special process that Tim mentioned earlier that allows them to rebuild the 2 series carriers with 3 and 4 series gears.
Don't forget to reprogram you PCM after the gear install, or else you'll be bouncing off the limiter at WOT.
My first C5 had 2.73's, I installed 3.42's. I liked the 3.42's, they are without a doubt the most popular gear choice for the A4.
My current C5 has 3.15's, and I just ordered 3.73's. Fun, fun, fun. I debated 3.90's but I thought they were a little too tall.
On a side note. 3.73's are only available from Getrag right now(the OE supplier to GM). Motive Gear, who makes the 3.73 ring and pinion for rebuilding differentials, has had some troubles with the 3.73's. So DTE has not built one in a while.
Here is a good gear calculator http://www.kabamus.com/garage/gears.html
Have Fun,
AZC5
PS. Sorry for the long winded post, I had too much coffee this morning!
