Manual Transmission T56 | T5 | MN12 | Clutches | Hydraulics | Shifters

Need Tranny advice!

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Old Jan 7, 2008 | 11:49 AM
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Default Need Tranny advice!

I have done a search,nothing conclusive so. Here is my question...I need a six speed to hold between 700-850 HP/TQ, and launches of 4-5grand on 10.5's. Ive been doing alot of reading about mn-12 and m-12 and th6060 or something like that. What is the most cost effective and or easiest combo? would it be the mn-12? or a built t56 with viper main shaft?
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Old Jan 7, 2008 | 12:11 PM
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The mn12 is still a t56 and both utilize the same size mainshaft (although not exactly the same). Basically the difference is the gear ratios and the mn12 uses triple cone syncros.

The f-body t56 will definately be cheaper to build, but the mn12 t56's are know to shift better due to the improved syncos. We can build an mn12 utilizing a custom mainshaft in order to make it "viperized" even though the viper shaft itself will not work due to the syncro design.

With either transmission, I would go with the larger output shaft at that torque level.
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Old Jan 7, 2008 | 12:37 PM
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My advice is usually different. The more cost effective way is to go with the Viper Conversion utilizing a LS1 transmission. Look at all of the viper guys we have built for. 4 in the last year are running the stock gear sets (same as the LS1 except the input shafts/output shafts) and all have been running 8.50's with the exception of one went 8.29@175 a few weeks ago. Now if you know much about the viper guys you know those guys are tough on transmissions.

I also advise the Viper conversion way and everyone is different. We have seen great things from them and will continue seeing great things.

The M12 will always shift better due to the triple cone blocker rings but I don't notice much difference from my 02 Camaro to my 02 Z06. For the cost the viper is the better way with that power level.

Call me if you need pricing or check out the website.


Amber
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Old Jan 7, 2008 | 01:14 PM
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I would go with the LS1 style unit as well with the Viper mainshaft and modified F body tail housing . As long as you use billet keys and bronze pads along with the steel fork , you should be fine . I actually prefer the LS1 ratio for higher powered cars and they are damn strong . I would think the weakest link in the unit would be the 2nd gear syncro teeth themself .

Make sure your clutch adjustment is on the money and you don't miss any gears and it should last for a long time .
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Old Jan 7, 2008 | 01:16 PM
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Ok I was not shure what was up with those.
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Old Jan 7, 2008 | 01:42 PM
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Originally Posted by Six Speeds Inc.
My advice is usually different.


Amber
I didn't recommend one over the other, I simply said that the f-body trans would be cheaper to build. With either one I would run the viper output.

To upgrade the mn12 the cost for the mainshaft alone (same that is used in Rocklands Tranzilla) would add $400 and the triple cone syncros would also add $300 to the cost of our $1400 viper shaft trans:

https://ls1tech.com/forums/sponsor-sales-specials/839513-crazy-sale-tick-performance-extreme-viper-t56-1400-a.html

Both will handle the expected hp/tq

Thanks,
Jonathan
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Old Jan 7, 2008 | 02:13 PM
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Originally Posted by thesource
I would go with the LS1 style unit as well with the Viper mainshaft and modified F body tail housing . As long as you use billet keys and bronze pads along with the steel fork , you should be fine . I actually prefer the LS1 ratio for higher powered cars and they are damn strong . I would think the weakest link in the unit would be the 2nd gear syncro teeth themself .

Make sure your clutch adjustment is on the money and you don't miss any gears and it should last for a long time .
Exactly. They do make a new style 2nd gear which has the better synchro teeth. They are longer than the old style and we have noticed don't cause any issues when you switch over to that one.

thesource, if you need that part number call me or pm me. That is the only we have used here are the shop.

Amber
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