What can a modified t56 take?
 

Hey guys quick question, what can a t56 with bronze fork pads, billet keys, a bronze shifter bushing, and steel forks. what kind of hp would a stock t56 with these upgrades take? Also are they worth doing? please let me know what you guys think.

Should be good for 450 rwhp I think it would need the viper input shaft to really bump it up.

I thought those were the stock numbers anyway? I thought for sure it would be around 500.

500 plus would work its all how you drive it.

I did a google search and didn't find the info I was looking for, but I seem to recall it being rated to 700 at the crank.

Have a look at, or even better call Texas Drivetrain Performance and ask. Good people.

http://www.texasdrivetrainperformance.com/

None of those upgrades does anything to increase the torque capacity of the trans. They really only help with shift quality.
As far as I know the only real torque upgrade for the LT/LS T56's is a mainshaft upgrade. They come with 27 spline outputs stock. You can go to the 30 spline viper mainshaft. A friend who works on GM manuals said there is a T56 that came in SSR truck that has a 32 spline main shaft.

I was advised to just buy a T56 magnum, because it already has all the upgrades.

That was my suggestion, gotta pay to play!

A T56 magnum has a torque rating of 750 ft lb....now that is a "safe" measurement I'm sure it could survive more then that depending on how you drive. Realistically do you need more then that for street use?
I realize that you aren't necessarily talking about a magnum but I'm willing to bet that by the time you get the "regular t56 and then rebuilding it you will have a similar amount of cash as purchasing a magnum in to it. Plus a magnum would be brand new not rebuilt and carry a warranty that wouldn't be as limited as one on a rebuilt tranny. It takes a bit to get to where you need to be....keep saving, I had to and, scored my self a magnum and a quicktime bell housing

I don't see how even a 30 or 32 spline makes the transmission stronger. The input shaft is still 1-1/8" and 26 splines. Youre only as strong as your weakest link. You will bust teeth off the gears before you shear a input or main shaft. The T56 Magnum's strength over OEM transmissions is mainly the gears.


Edit....I found this http://www.moderndriveline.com/Techn...s_improved.htm

Typically when you increase the spline count you will increase the contact area. Think of a 4000 lb car on 4 275 tires verses 4 205 tires...which one has more contact area to apply to the pavement. I know not the best example but you get the idea. Now having said that the magnum uses a much beefier shaft and larger gear face while still using the way more popular 26 spline input shaft. Allowing the aftermarket to continue with their current product lineups

Because the output shaft sees mulitple times the torque the input shaft sees. If you have a 2.66 first gear and 500 ft.lb. of torque at the flywheel, you'll have 500 ft.lb. on the input and 1330 ft. lb. of torque at the output shaft.

The T56 magnums strength comes from almost everything in the trans, not one single part.

No Magnum parts available?
 

Does no-one find it disconcerting that you or I can't order individual parts for the Magnum? That scares me away from the Magnum. I've been digging all day. D&D sells a few parts but not many.

I'm curious to know what is needed to convert a T56 to a T56 Magnum if I already have a tail house. Already know I need the mainshaft, but albeit the parts on that shaft are all different due to larger diameter.

I am not sure that a regular T56 can be turned into a Tr6060 (Magnum). The Magnum uses a different case, has gears are wider and the synchro design is different.

If you want a high HP T56, look at the G-Force internals.

http://www.gforcetransmissions.com/tran_gt-56.asp

Andrew

true, having 1.5 teeth in the place of 1 tooth provides more gear surface contact. Making it much more resistant to clashing and shearing.

Thanks. It made me curious. I'm about to tear into my first manual transmission and im trying to absorb as much info as possible before I proceed. Lol.

I could easily jump in and buy a new Magnum and be done with all of this....but at the same time I see this as a benifit in the future if I understand the internal working process of a manual and modify my existing T56 with all the best that GMs OEM had to offer. In my case I've been looking at using the internals from another T56 out of a C6 and going with a SSR output upgrade, then I can keep my existing TH400 driveshaft.

I'm still weighing the options. I have a headache. Lol.

Well guys a magnum costs 3300 not bell housing or accessories, the rebuild is 1000. Not to mention when I rebuild it I can use it and sell it in a few months for 2000, opposed to the 500-600 I could have gotten for the trans that needed a rebuild. My engine has only 400 hp when I upgrade my motor I will be sure to get a magnum. Until then I think the stick t56 will be ok, but we will see.

The mainshaft is the weaklink once you put in a steel 3/4 shift fork. If you launch hard on slicks beyond 600rwhp you are on borrowed time.

That being said a customer of mine never broke a stg2 T56 I built with basic upgrades. Mellow launch and 9.20s@162mph in a 3000lb car. Gts76 Turbo ls3 rx7.

Supposedly at 3500lbs the Mainshaft (output shaft) limit for repeated abuse is about 600rwhp/tq on slicks. An upgraded viper 30 spline shaft is reliable to about 900rwtq... Beyond that the gears are the weak link. Especially 5th in top speed high hp racing.

There are a bunch of twin turbo Vipers running stock T56s into the 8s. How long they last is a roll of the dice.

If you have the $.... A T56 magnum is a very nice shifting transmission. I'm putting over 1100rwhp thru mine.