Viper T56 Trans info

[Chryco Psycho]

Ok, so I have done much research on why the viper box is the "desired box". So I will break down the differences based on year.

This is a quote from a Tremec Rep which breaks down most of the differences.

" The T56 transmission differences between the Viper, Firehawk and Cobra are: 
The Firehawk and Viper have the same gear ratios, which include a .74 5th and .50 6th gear.
The 2003 Cobra has a .80 5th and a .63 6th gear. First through fourth for these vehicles are the same.  The Firehawk and Cobra have the same output shaft size (27 tooth spline), the Viper has a 30 tooth spline.

The most important difference is the synchronizers. The Cobra and Viper have carbon synchronizers. The Firehawk (and other GM T56 transmissions) used paper synchronizer material through model year 2001. Carbon is more aggressive, but the paper gives a smoother shift. It is extremely important to only use recommended oil with paper synchronizers. Dexron III ATF is the recommended oil. Mobil 1 ATF is the only recommended synthetic oil. Using the wrong oil with paper synchronizers will cause the paper to degrade very quickly. It is a compatibility issue with some oils.

The Viper has a single piece countershaft where the GM and Ford transmissions have a two piece countershaft construction. There are bolt pattern differences, but essentially the rest of the transmissions are the same.  I hope this answers your question.   

John Loeffler"     OK, now on with the rest of the show.

The GM LS box never really changed and it's output rating remains the same (450ft lbs). This holds true for the ZO6 boxes, even with their triple cone syncro setup, in earlier years still carried the 2 piece counter shafts. Not until the 7.0 LS version did the box get the viper style, beefy one piece countershaft.

There is a rumor that the very earliest viper boxes pre 1996, also had the split countershaft.

The Viper box went thru a series of upgrades as time went on, but it's advertised torque rating stayed the same at 550 ft.lbs. The first was in 1997 with the addition of a steel 3-4 shift fork, and bronze shift pads on the shift forks.

The next VT56 upgrade was in 1999 that's when it received the carbon fiber blocker rings.

The last change was in 2003+ transmissions, the 5th and 6th gears are pressed on to the shaft and are wider for for increased strength. This trans also has a fixed rear yolk. So truth be told, the later viper boxes are a better buy.

So, the real reason for the viper spec t56s increased strength, results from the one piece countershaft. There is a certain website that states there is no such thing as a viper spec box. They are simply wrong. There are notable differences.

Does it mean there are no worth while upgrades for V-spec boxes, no. There are 2 worthwhile mods for strength.
Billet shift keys are probably mod number one. These little fellas hold the transmissions in gear, and prevent it from popping out of gear. The factory ones are stamped steel and known to deflect.

The next real strength mod, for a VT56 comes from installing wider 9310 gear sets. The increased width gets you well and above 700 ft lbs of torque  capacity.

Mods that help shift feel are the 1-2 triple cone upgrade, 3-4-5-6 double cone, and finally a bronze shifter cup. These mods don't necessarily increase strength; but do help shift quality and rpm thresholds before the dreaded grind shift.

For us mopar guys the viper trans is nice because it comes with a proper input shaft, the same output shaft as HD 727s,  the V10 bell housing has the same bolt pattern as the the 5.2/5.9/gen 3, and in Stock for will more than handle what most of our engines can throw at it.

I also wanted to point out that you can start with a cheaper LS unit, but you will need to swap out some parts to make it work.

The Viper/mopar input shaft is the biggest hurdle, as well as the different output shaft. These will run almost 1k in parts, however the shift pads is much farther back which is a plus for B/E bodies.

Also Tremec's rating system is pretty impressive. They subject the transmissions to a 24 hour WOT torture test. The torque they rate them for is the safe maximum for the tests duration, which gives you an idea of the T56 magnums true potential.

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[GoodysGotaCuda]

Nice write-up. If I ever get some spare time, it'd be nice to have a similar post on the latest Tremec, the TR6060/T56 Magnum.