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.