Heres a discussion I think I would find intresting.

Recent disucssions with a friend of mine discussion a T-56 vs TH400 (yes i know, 2 different worlds). Anyway, I was leaning towards the T-56 so i could get some solid road racing in and not worry as much about a trans overheating at 6700 rpms for exteneded periods of time- well less so anyway.

Discussion moved on into drag racing where he felt it was a terrible choice. His reasoning- First gear was way too tall, expecailly for a high revving motor such as mine. Trying to get the wheels to hook up at 4000rpms and 30mph for example would be a lot harder of a shock than 4000 rpms and 15mph. I wouldn't want to launch at 2000 rpms and have to climb up through the powerless part of the power band. His "case and point" was his friends Gt they put a t-56 in. The car saw a bit of milage and highway cruising so they went for it. The car lost a few tenths and a few mph in the 1/4. yeah, they were upset. And they bumped up the rear gear to the point where thy were pretty much back where they started as far as the OD went.

I argue the t-56 is well suited for a camaro due to the fact that the Lt1 has a lot more torque down low. The weak rear had might of had something to do with the first gear from GM's durability standards (what little there was) as well. He agreed partially. However my motor will share few powerband charactoristics with a stock LT1.

Someone correct me if i am wrong, but there 3 gear ratios in the t-56.

a 3.3x and 2.9x and a 2.66? the first two coming from 93's only. The t-56 I picked up is from a 93, i am unsure which. At this point, in your opinion, would i better off with another transmission or sticking with te T-56.

I havn't seen too many T-56 threads in here and I would hate to just assume it is as great on tht basis. So please, discuss! afterall, "The unexamined life is not worth living"- (That one is for you JB )

 

get the 3.36 first if you want a deep first gear.

 

T56 is a great street and open track tranny. It was never ment for drag racing, and can not hold up to high torque full throttle shifts like a T10 or Jerico or similar can, thats why they break....as far as gears go, well any serious racer is going to select ratio's for his or her car and the setup they have.....you do not have that choice with the T56 at this time. You just have a couple choices of what ever they offered for OEMs.

As far as RR goes...it works pretty good, needs a cooler for cars that are really going to spin it but it does work. Like I said above if your going to get really serious then your probably going to pick a Hewland or GForce so you can pick your ratio's and it will also have a little less rotating mass to go along.

The LS1 cars with the Tremec versions have a lot of issues after BW sold everything and Tremec builds them in Mexico so I'm sure that has tarnished the image a little bit. The BW units in the LT1 cars seem to hold up a little better and don't have as many problems in the more modd'd cars...but thats just my own opinion since my dad worked for BW.

 

I agree with above. If you are going to build a pretty much all out race car you should look into getting a richmond or something that is "ment" for beating on.
Depending on how much you road race I would get a TH400 or even a TH350. Trans-brakes are cool. s

 

jordon i didnt know you guys had a shop now....cool!

 

Trey, believe it or not, the 2.66 is actually the best choice for drag racing. It comes very close to a muncie close ratio 4 speed in terms of ratios. YOu want the close ratio so that you don't lose as much RPMs between shift and stay around your power peak. You run a lower rear gear to compensate for the 2.66 1st. The double overdrive keeps your gas milage on the street in check. I love the T56. The wide ratios like 3.36 where designed for gas mileage and running a numberically lower rear gear.

I don't know what Road racers do because i know my tranny will start to overheat (tighten up a lil) if i run it really hard a med hot day. I'm talking 30 mi of ***** out backroads with 5k rpm shifts WOT most of the time. I just decided i don't need to drive around that fast for that long and we won't have that problem.

 

Trey -- Not sure if you already knew this or not, but the 1993 t-56 trans is rated at a lower TQ rating than the 94-97's. The standard T-56 in 1993 was rated at 350ft/lb TQ and the G92 version (shorter 1st gear, came standard with the 3.23 rear) was rated at 400ft/lb TQ.

This is compared to the 450ft/lb TQ rating of the 94-97 trannies.

Just an FYI.

Pete.

 

Yes thats true too according to sallee chevrolet. Another reason for the close ratio.

 

This may help ya find the one you want Trey

RPO M28 3.36 1st 1.35 second
RPO M29 2.97 1st 1.44 second
RPO MM6 2.66 1st 0.50 6th.

 

what modifications would allow a T56 to stand up to say 500 ft/lb torque? i have recently noticed mine making a very faint grinding noise on a 1-2 shift if i dont let the RPMs drop any... its fine if i wait a sec or 2 before going into 2nd but that makes me feel like i cant drive. i am guessing this is syncros wearing out.. am i correct?

 

All 1LE cars got the MN6s....just FYI

As far as beefing them up. Well shift steel shift forks, and better syncro's (if you have to do slow shifts then more than likely yes it is the syncro's going out). Go to a good fluid (I use GM Syncromesh) and if you are going to be doing a lot of extended high speed stuff install a cooler (GM has them in the parts catalog if you don't want to fab one up). Have a good clutch and don't bang gears all the time. Like I had said above..its never going to be a crash box like a old M22 Muncie. I had heard one guy talk about a better input shaft but there again you are still just patching parts and not solving the problem...if thats what you want to do.

Plenty of guys have put a lot of power thru them and had them last, they just know how to drive them or never really got a really serious tire on the car.

Pick how you want to drive and pick a tranny for it.

 

Is the MN6 any different than the T-56?

 

no MN6 was the RPO code for the T56
I think the other guy had it listed as the MM6
2.66 first
1.78 second
1.30 third
1.00 forth
.75 fifth
.50 six

rated at 450+ft-lbs

 

looking at the camaro parts manual right now, it says MM6, mabye MN6 is a corvette RPO?

 

MN6 just a model number (or label) for one specific trans that GM used. it was mn6 in the camaro and m12 in the vette.

my favorite, for obvious reasons would be the MN6, or 2.97 first gear, .050 OD 6th. Very easy to rebuild, install, nice to drive, yields great gas mileage, ( even w/ 4.33's) and takes one heck of a beating if you drive it correctly. i definately beat the holy heck out of mine, but as long as you know the limitations of the parts your working with, or at least know how to repair them, treat it however you want to. they'll take 500+ RWTQ easily, beleve me, i know. they will break eventually, but a decently prepped t-56 can run in the 9's and hold up to high 1.20 60' times.