changing the Diff gearing

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Apr 8, 2007 | 10:58 PM

#21

tiojames

Team Owner

Joined: May 2005

Posts: 23,682

Likes: 9

From: Flagstaff Az.

Quote:

Originally Posted by hornet7

My car is a 6 speed, the gearing is 3.42 and I thinking of going to 390's.

Don't forget to post your 3:42's here in the forum. The guys with autos will buy them. Depending on the mileage, you can get $350-500 for them to help offset the cost of a new diff-$1100-1200. A new diff is the way to go because you get new bearings, posi, etc.

Apr 9, 2007 | 01:20 PM

#22

TYSON1997

Racer

Joined: Mar 2006

Posts: 464

Likes: 0

From: silverdale washington

If you are going to buy a new rear end instead of just swapping gears I would just spend the money on an m12 tranny. You would be much happier. You have the lower gears where you need them but your 5,6th gears are still for good gas mileage.

Apr 9, 2007 | 01:27 PM

#23

Mike Mercury

Team Owner

Joined: Apr 2001

Posts: 54,204

Likes: 180

From: S.W. Ohio. . . . . . NRA Life Member

Quote:

Originally Posted by TYSON1997

hmmm... interesting idea.

Apr 9, 2007 | 04:05 PM

#24

hornet7

Thread Starter

Racer

Joined: Feb 2004

Posts: 348

Likes: 6

From: Las vegas Nevada

Gearing

Currently my Transmission is being rebuilt with performance (Z06) upgrades. I plan on changing the gearing to match my lust for Freeway on-ramp speeds. If this is the same as an M12, we're good to go. If not, I will need to dig further into my upgrade. My local Corvette specialty is doing the work. My power train upgraded started with my 1st and 2nd Synchros giving me problems. So, I also planned on replacing my Clutch and pressure plate while the car was in the shop. This upgrade is growing to replace and/or upgrade to performance parts in the diff as well. So, I've replaced my Clutch, Transmission parts, and Diff gear ratio (3.79) and any obviously warn components. Any suggestion that I've missed?
Thanks

Apr 9, 2007 | 04:41 PM

#25

wettvette

Instructor

Joined: Dec 2004

Posts: 235

Likes: 0

From: Auckland

Quote:

Originally Posted by NOS500

I have a stock engine, and I installed the 4.10's and I love them. The 4.10's keep the rpms in the perfect spot. The gas mileage has gone down about 1 mpg so its not too bad.

should be how the car left the factory new

Apr 9, 2007 | 05:07 PM

#26

fdxpilot

Safety Car

Joined: Jul 2001

Posts: 4,661

Likes: 67

From: Ocean Springs MS

Quote:

Originally Posted by hornet7

So, I've replaced my Clutch, Transmission parts, and Diff gear ratio (3.79) and any obviously warn components. Any suggestion that I've missed?
Thanks

One more time. I'll speak slowly.
There is no such thing as a 3.79 gear ratio for a Gertrag Corvette rear end.
Any shop that tells you so does not know what they're doing. Your choices are 2.73 (stock A4,) 3.15 (opt A4,) 3.42 (stock MN6,) 3.73, 3.90, and 4.10.