Gear question
Thread Starter
Pro
Joined: Oct 2004
Posts: 585
Likes: 0
From: Englewood Florida
Gear question
I have a 99' coupe A4 with the 2.73 rear end. I would like to know where i can get a new one with the 3.15 or 3.42? What brand should i get and how much work is involved in replacing them?
Melting Slicks
Joined: Sep 2002
Posts: 2,329
Likes: 0
In my 2000 coupe (A4) I went from the 2.73's to 3.42's. The other choice you mentioned is not big enough to warrant cost. Had hardened shaft installed at the same time to save labor charge. You might consider a torque convertor as well. I didn't and now I have to get one installed. Dumb move on my part. The Yank SS 3500 is a good model. Ask on the forum about this mod. Also go on the website for your area of the country and get some suggestions on local shops that do this work. If you do it yourself you are a better man than I!!It should did a LS1 edit as well.
Team Owner
Joined: Apr 2001
Posts: 54,204
Likes: 180
From: S.W. Ohio. . . . . . NRA Life Member
Pro
Joined: Feb 2003
Posts: 644
Likes: 10
From: st. cloud mn
skip the 3:15 for sure but be careful if someone leads you to a 3:73! Mike Mercury is a guru of sorts and his advice has helped me. He is willing to help the new and the old folks around here and knows way more than most!
Melting Slicks
Joined: Jun 2001
Posts: 2,743
Likes: 3
From: Davie Florida
Originally Posted by Gimmesum HP
Why skip the the 3.73? Lots of poeple on here running that ratio and love it.
3.73 gears should also be considered especially if you don't do a great deal of highway driving. I have 3.73 gears in my car and I like them very much.
Safety Car
Joined: Jun 2004
Posts: 4,353
Likes: 22
From: Bella Vista Ca
I just installed a new Zo6 3.42 form TByrne (forum vender). I got the diff for about $1025 shipped through price matching. If you want to save some money on used parts look on ebay or they turn up in the forum for time to time. New diffs are factory GM Getreg. That is the only new complete diffs I've seen for sale. The 3.42s really make a world of difference in the SOTP feeling. 
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Pro
Joined: Mar 2004
Posts: 675
Likes: 0
From: Talty TX
Another option is GM Parts Direct, another Forum vendor. You can get a brand new ZO6 3:42 Getrag unit for < $900....
GM PART # 12572683
CATEGORY: Differential Carrier
PACK QTY: 1 CORE CHARGE: $0.00
GM LIST: $1,559.95
OUR PRICE: $889.17
DESCRIPTION: DIFFERENTIAL CARRIER
GM PART # 12572683
CATEGORY: Differential Carrier
PACK QTY: 1 CORE CHARGE: $0.00
GM LIST: $1,559.95
OUR PRICE: $889.17
DESCRIPTION: DIFFERENTIAL CARRIER
Team Owner
Joined: Apr 2001
Posts: 54,204
Likes: 180
From: S.W. Ohio. . . . . . NRA Life Member
GM PART # 12572683
CATEGORY: Differential Carrier
PACK QTY: 1 CORE CHARGE: $0.00
GM LIST: $1,559.95
OUR PRICE: $889.17
DESCRIPTION: DIFFERENTIAL CARRIER
CATEGORY: Differential Carrier
PACK QTY: 1 CORE CHARGE: $0.00
GM LIST: $1,559.95
OUR PRICE: $889.17
DESCRIPTION: DIFFERENTIAL CARRIER
Last edited by Mike Mercury; Oct 15, 2004 at 09:50 AM.
Burning Brakes
Joined: Aug 2001
Posts: 1,206
Likes: 21
From: Roswell GA
3.73's
I certainly can not pass up a gear post.
If you are going to mess with your engine (heads, cam, FI, etc) and/or drive 50% highway - go 3.42
If you are like me - stock engine - mostly just rod around town - those 3.73's will turn heads and put a grin on you and anybody who rides along. Makes the car real quick and fun. You must have "rubber burn" foot control or alot of cash for tires. But I never spin unless I want to.
I have had 3.15's, 3.42's, and now 3.73's. I would not go higher, but I would not go back either.
If you are going to mess with your engine (heads, cam, FI, etc) and/or drive 50% highway - go 3.42
If you are like me - stock engine - mostly just rod around town - those 3.73's will turn heads and put a grin on you and anybody who rides along. Makes the car real quick and fun. You must have "rubber burn" foot control or alot of cash for tires. But I never spin unless I want to.
I have had 3.15's, 3.42's, and now 3.73's. I would not go higher, but I would not go back either.
Last edited by KingTut; Oct 15, 2004 at 05:13 PM.
Team Owner
Joined: Aug 2003
Posts: 38,314
Likes: 35
I can't pass up a gear post either.
The shipping charges need to be taken into account with the GM parts direct price.
Going from 2.73s to 3.73s won't be cheap. In part because you cannot change the 2.73s for the core charge. A 3.73 diff will cost you about $1900.00. A 3.42 diff will go for about $1020.00.
The shipping charges need to be taken into account with the GM parts direct price.
Going from 2.73s to 3.73s won't be cheap. In part because you cannot change the 2.73s for the core charge. A 3.73 diff will cost you about $1900.00. A 3.42 diff will go for about $1020.00.
Pro
Joined: Mar 2004
Posts: 675
Likes: 0
From: Talty TX
Originally Posted by Mike Mercury
is that a typo? Has anyone actually ordered a #12572683, and received a #12572683 carrier for $889.17 ???
Advanced
Joined: Jun 2003
Posts: 93
Likes: 0
Originally Posted by Gimmesum HP
Why skip the the 3.73? Lots of poeple on here running that ratio and love it.
I have 2.73 gears in mine as well and hate to change it because my car is a daily driver and I *LOVE* the gas mileage.
Thinking about a 50hp dry shot instead
**Important Caveat: You will have to have your PCM programming changed if you bump the gears from 2.73 to 3.73.
Drifting
Joined: Sep 2002
Posts: 1,947
Likes: 0
From: Howell MI.
Originally Posted by camiv
skip the 3:15 for sure but be careful if someone leads you to a 3:73! Mike Mercury is a guru of sorts and his advice has helped me. He is willing to help the new and the old folks around here and knows way more than most!
Its Choices
I had a stock 6 sp 3.42 in my a4 and now have the 3.73 and would never go Back.
Burning Brakes
Joined: Dec 2001
Posts: 1,054
Likes: 0
From: Mt. Juliet TN
St. Jude Donor '05
Originally Posted by blktie8
Explain whats wrong with the 3.73 in an a4
Its Choices
I had a stock 6 sp 3.42 in my a4 and now have the 3.73 and would never go Back.
Its Choices
I had a stock 6 sp 3.42 in my a4 and now have the 3.73 and would never go Back.
Instructor
Joined: Apr 2003
Posts: 179
Likes: 0
From: port orange fl
I have a 1997 A4 with 2.73 rear gear. My question, is there a core charge to purchace a new ZO6 3.42 upgrade?? (GM Parts Direct)
Also anyone have a idea of what cost should be to do swap and reprogram computer for this year car??
Also anyone have a idea of what cost should be to do swap and reprogram computer for this year car??