T56 differential
Tech Contributor
Joined: Dec 2003
Posts: 19,384
Likes: 87
From: Horncastle Lincolnshire, England
2023 C5 of the Year Finalist - Unmodified
The T56 is the manual transmission built by Borg Warner. I think the diff is built by Getrag.
Is your question whether the diff can be modified with different gearings? If so the answer is yes.
I guess "simple" depends on your mechanics skills. Its not a job I'd tackle but plenty on the Forum have done the mods. I'm sure others with more info will comment.
Different ratios were offered on new C5s and given different RPO codes:
G90 Axle, Rear, 3.15 Ratio (Option for the Auto)
G92 Axle, Rear, Performance Ratio (Z06 IIRC)
GU2 Axle, Rear, 2.73 Ratio (Base model for the Auto)
GU6 Axle, Rear, 3.42 Ratio (Manual)
Mine for example had the ISC package which included G90 with 3.15 ratio.
HTH
Is your question whether the diff can be modified with different gearings? If so the answer is yes.
I guess "simple" depends on your mechanics skills. Its not a job I'd tackle but plenty on the Forum have done the mods. I'm sure others with more info will comment.
Different ratios were offered on new C5s and given different RPO codes:
G90 Axle, Rear, 3.15 Ratio (Option for the Auto)
G92 Axle, Rear, Performance Ratio (Z06 IIRC)
GU2 Axle, Rear, 2.73 Ratio (Base model for the Auto)
GU6 Axle, Rear, 3.42 Ratio (Manual)
Mine for example had the ISC package which included G90 with 3.15 ratio.
HTH
Last edited by DeeGee; Feb 19, 2010 at 02:16 AM.
Tech Contributor
Joined: Aug 2008
Posts: 2,902
Likes: 21
From: Oak Hill Virginia
Thread Starter
Racer
Joined: Jan 2010
Posts: 324
Likes: 2
From: Moreno Valley CA
Okay.....so being new to the corvette community I am all for doing some research (or picking brains on here). Someone is selling a "T56 differential for C5 corvette." So it's probably a differential from a manual corvette? And, if so, will it bolt into a car with an automatic?
Tech Contributor
Joined: Aug 2008
Posts: 2,902
Likes: 21
From: Oak Hill Virginia
Okay.....so being new to the corvette community I am all for doing some research (or picking brains on here). Someone is selling a "T56 differential for C5 corvette." So it's probably a differential from a manual corvette? And, if so, will it bolt into a car with an automatic?
Thread Starter
Racer
Joined: Jan 2010
Posts: 324
Likes: 2
From: Moreno Valley CA
Well, keeping my fingers crossed. Just bought it. Granted....this is their "story" but I got it for less than $400 including shipping and was told it probably had 10k or less miles. Now I just gotta wait (patiently) for that to come in before getting the suspension installed, car lowered, pumpkin put in and full tune.
Still wondering, is there a difference in the differential for automatics vs manual trans or will it bolt right up?
Still wondering, is there a difference in the differential for automatics vs manual trans or will it bolt right up?
Tech Contributor
Joined: Oct 1999
Posts: 41,058
Likes: 9,819
From: Charlotte, NC (formerly Endicott, NY)
Should bolt right onto the transmission. There was an extension housing between the manual transmission and the differential. They did this as the manual transmission was shorter than the auto. That also allowed them to have the same mating surface and bolt configuration as the auto.
Bill
Bill
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
Melting Slicks
Joined: Feb 2003
Posts: 2,966
Likes: 22
From: Frederick Maryland
St. Jude Donor '08-'09-'10-'11
The 3.42 diff will bolt right up to your auto. Just make sure to transfer the plate that seperates the trans from the diff. This is a round aluminum piece with a large o ring seal that will be on the diff side. It will have a "trans side" on it. Transfer this to the new diff and you are good to go! 
