mn6 to mn12
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From: Fort Wayne IN
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Should be a direct swap. The biggest difference of the two transmissions is the internal gearing.
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Joined: May 2005
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From: West Norriton PA
St. Jude Donor '08
Race Director
Joined: May 2005
Posts: 15,960
Likes: 21
From: West Norriton PA
St. Jude Donor '08
Tranny is either a MN6 or M12, their is no MN12. A gear swap in the rear to 3.90's would probably bring you on par gear wise with M12 if you had a MN6.
Cars with FI should probably stick to 3.42 or less, due to traction.
Burning Brakes
Joined: Aug 2004
Posts: 770
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I did the swap a couple of years ago when my MN6 failed. One thing slightly different is the shift linkage connection at the trans. I think we had to drill out one side slightly larger. You will see when you do it, and it is easy.
Burning Brakes
Joined: Jan 2007
Posts: 833
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From: Boca FL
http://www.zo6vette.com/forums/showthread.php?t=60015
M12 6-Speed Manual
This transmission is unique to the Z06, and is the only transmission available for that model. It is not available on Corvette coupes or convertibles. It has more aggressive gearing to increase torque multiplication in most forward gears, allowing for more rapid acceleration and more usable torque at higher speeds.
A transmission temperature sensor was added to protect the M12 from higher thermal stresses. The sensor warns the driver via the Driver Information Center with a TRANS OVER TEMP light if thermal loads become excessive, meaning that the transmission could be damaged if not allowed to cool down.
Gear Ratios
LS1/MM6 LS6/M12
1st Gear 2.66:1 2.97:1
2nd Gear 1.78:1 2.07:1
3rd Gear 1.30:1 1.43:1
4th Gear 1.00:1 1.00:1
5th Gear 0.74:1 0.84:1
6th Gear 0.50:1 0.56:1
Reverse 2.90:1 3.28:1
M12 6-Speed Manual
This transmission is unique to the Z06, and is the only transmission available for that model. It is not available on Corvette coupes or convertibles. It has more aggressive gearing to increase torque multiplication in most forward gears, allowing for more rapid acceleration and more usable torque at higher speeds.
A transmission temperature sensor was added to protect the M12 from higher thermal stresses. The sensor warns the driver via the Driver Information Center with a TRANS OVER TEMP light if thermal loads become excessive, meaning that the transmission could be damaged if not allowed to cool down.
Gear Ratios
LS1/MM6 LS6/M12
1st Gear 2.66:1 2.97:1
2nd Gear 1.78:1 2.07:1
3rd Gear 1.30:1 1.43:1
4th Gear 1.00:1 1.00:1
5th Gear 0.74:1 0.84:1
6th Gear 0.50:1 0.56:1
Reverse 2.90:1 3.28:1
Racer
Joined: Mar 2006
Posts: 464
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From: silverdale washington
DRR is right when you hook up the shift linkage to the tranny the hole in the shifting input shaft is to big. You have to drill the hole out on the shift linkage to the same size as the shiftting input shaft and use a bigger pin. Very easy to do though, you can just measure the hole and go to lowes or home depot and find a pin that is the same size as your drill bit. Also while you are in there you may want to do a clutch if you plan on adding more power or at least a slave cylinder and remote slave cylinder bleeder.
Race Director
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From: West Norriton PA
St. Jude Donor '08
Melting Slicks
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From: cincinnati ohio
Tech Contributor
Joined: Mar 2003
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From: Colorado Springs, CO
St. Jude Donor '08-'09-'10-'11
Actually they should gear for the trap speed and stop adding power when they cant get the power to the ground anymore. 60's fall with gearing. Gears slow the rotation speed of the tire which lets you hook faster (actually it hooks when the car reaches the speed that the tire rotation is at).
Burning Brakes
Joined: Aug 2004
Posts: 770
Likes: 0
The male and female linkage couplers are different sizes. I had to drill it out and use a larger pin than what my '98 originally had.
They must have changed this sometime after my 3/98 build date.
If you have not swapped a 3/98 or earlier MN6 to an '05 M12 - may explain why you may not have seen it.