Rear differential swap
Thread Starter
Race Director
Joined: Dec 2005
Posts: 11,664
Likes: 15
From: Wellsboro Pa
Rear differential swap
I currently have a 98 with A4 and 2:73 gear ratio. If I were to change the ratio to the 3:15 what other changes would be required? What about the speedometer calibration?
Intermediate
Joined: Nov 2006
Posts: 32
Likes: 0
rear gear swap
hey!!!!!!!!!!! i got this one!!!!!!
got ready to do this, got boned on the used rear end, trying again in a few months. here was my plan:
according to many people doing this, the 3:42's are best, sotp feel. more significant than with the 3:15's
Next step is to use "LS1 edit", to change shift points and electric cooling fan starts (since you're already using the program that can do it!!), then you're done!!!
call A&A in SoCal, they're great, and can tell you all about it, or email me, i'll tell you all you wanna know, greg
got ready to do this, got boned on the used rear end, trying again in a few months. here was my plan:
according to many people doing this, the 3:42's are best, sotp feel. more significant than with the 3:15's
Next step is to use "LS1 edit", to change shift points and electric cooling fan starts (since you're already using the program that can do it!!), then you're done!!!
call A&A in SoCal, they're great, and can tell you all about it, or email me, i'll tell you all you wanna know, greg
Last edited by ragtopman4; Dec 31, 2006 at 01:42 AM. Reason: corrected poor grammer and spelling
Melting Slicks
Joined: Jun 2001
Posts: 3,123
Likes: 3
From: Orland Park Illinois
St. Jude Donor '06-'07
Go w/ atleast a 3.42 rear gear. No need to recal the speedo. However, your shift points will need to be recalibrated. I've had a 3.42 in my '98 A4 for about 6 years now. It was a very good move to make. Good luck w/ the swap....
Team Owner
Joined: Mar 1999
Posts: 22,025
Likes: 192
From: At the beach in little Rhody
If you go with the 3.42's, why not just buy a brand new Z06 rear from one of the forum GM parts vendors. The cost is a bit more, but in my mind worth it because you have a brand new part as opposed to one you are unsure of how it was treated.
Le Mans Master
Joined: Aug 2000
Posts: 5,294
Likes: 2
From: Suffolk, Long Island NY
People have reported noisy ones straight from GM.
Drifting
Joined: Nov 2003
Posts: 1,539
Likes: 3
From: South al
u can pick up a used 3.42 carrier on this forum for aroun 600.00 to 750.00 maybe cheaper.Then put @ least a3200 stall in it & u wont have any regrets other than maybe to go bigger on the stall jmo u will also get about 100 diffrent answers on which one is best .If i could ride in a car that has a stall & a gear then theres no doubt on what i would do
Last edited by fsuforever; Dec 31, 2006 at 10:48 PM.
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Burning Brakes
Joined: Dec 2003
Posts: 855
Likes: 0
From: Tampa FL
Melting Slicks
Joined: Jun 2001
Posts: 3,123
Likes: 3
From: Orland Park Illinois
St. Jude Donor '06-'07
A 2.73 A4 will run @ approx. 1685 rpm @ 70 mph. A 3.42 A4 will run @ 2110 rpm @ the same speed. These speeds/rpms assume you have stock rear wheel diameters, you're in 4th gear and the road is level. Good luck...
Premium Supporting Vendor
Joined: Mar 2001
Posts: 5,241
Likes: 21
From: Knoxville Tennessee
This is the way to go.
Le Mans Master
Joined: Aug 2004
Posts: 8,506
Likes: 5
From: West Michigan crew Mich
CI 7-8-9 Veteran
St. Jude Donor '07-'08 & '12
I took my car to DTE and they put 3.73s and vig 3200 converter in my car. The change was unbelieveable. From a 20-25 mph roll I can light the tires by just standing on the gas. I have a pretty stock engine cai and headers is all I have. Took it to the strip just once on a very hot day and put it in the 12s on my street tires. I take it on trips and it runs down the interstate just fine. At 75 mph I am at about 2300 rpms. The only draw back is I am going need tires
Drifting
Joined: Nov 2003
Posts: 1,539
Likes: 3
From: South al
heres your carrier in the parts section :http://forums.corvetteforum.com/show....php?t=1586444 well looks like rodney has dibs on it but u can pic them up on the forum fairly cheap
Burning Brakes
Joined: Nov 2006
Posts: 880
Likes: 0
From: Detroit Area Michigan
Listen to Slolane, he offered to let me drive his car to check out what gear I should get. To go more than 273, I hear that you need the larger carrier, like the one for the Zo6's. Yankeevette lives closer than Slolane and also offered me a ride in his car, called him on Thursday, during the holiday, he said come over, when I got there he said " Hi, I'm Dick Nunez, let's go!" he handed me the keys and now I know that I'm getting 373 gears! Your answer is of course, find somebody close by, go for a ride, then decide. For all the money that you will spend to go with the 3.15's, IMHO, it's not worth it. If I had my gears in now, I'd give you my 3.15's, next year, I'm sorry it's almost next year now...Bob
Gohard, or don't go at all!
Gohard, or don't go at all!
Thread Starter
Race Director
Joined: Dec 2005
Posts: 11,664
Likes: 15
From: Wellsboro Pa
A lot of excellent information from you guys, thanks. Another question, is the differential carrier the same for both the automatic transmission and the manual transmission?
