1gary

What yrs and models should I look for and are there any crossovers that I could use??. My plans is to do a search in Car-Part.com

sofakingdom

iTrader: (1)

94-97 Z28 or TransAm is the usual choice.

Mine's a 96 if memory serves. Has the 2.6x 1st, and .7x & .50 ODs.

DeltaElite121

Mine was from a 95. Get that transmission checked out when you grab it because a lot of these transmissions need serviced and fixed at this point, and it's not cheap.. Even if you're doing it yourself. I'd never buy a T56 online unless it was a rebuilt unit. Used ones online are usually steep pricing.

Sofa, I think 94 has different ratios doesn't it? I can't remember.

1gary

Do I have this right??. The T56's have three different shifter locations??. You know they have shifter plates on the top of the trans??. Or am I confused that only Tremic has that or is a T56 a Tremic??.

jmd

iTrader: (4)

You can have any shifter position you want if you don't mind custom work.

If it's for a third-gen, the F-body LT1 units are a solid way to go with no fab.

UnstableAviator

The T56 in the 1993 F-bodies is the least desirable unit out there. Its got a steeper 1st gear ratio and is rated for less torque than the later transmissions. Stay away from a 1993 would be my advice.

1994-1997 LT1 style T56 transmissions are the best option for a conventional SBC setup. As someone said, they are all getting long in the tooth and chances are you'll need a rebuild. I believe these were made by Borg-Warner and then that company was bought out by Tremec sometime in the late 90's.

The 1998 and up T56 are LS1 specific. The mid-plate and input shaft are different (input shaft longer) but otherwise they are internally the same as the 1994 and up unit. If you find one of these for a great price, you can always change the mid plate and input shaft and you're right where you need to be for n SBC install. Heck, I've even got those parts sitting around collecting dust.

Dyno Don

iTrader: (7)

I often wonder where that stuff came from on the torque ratings.

This is the trans I have in my car "1386-000-011"
I have 400/430 RWHP & TQ and launch at 5k+

Look at the specs for all the torque ratings at this site
http://www.moderndriveline.com/Techn...remec_t-56.htm

sofakingdom

iTrader: (1)

I pay NOT THE SLIGHTEST attention to any of those "ratings" fantasies.

Right, 93 is the one with the different (poorer) ratios. Regardless of any "ratings", its ratios are simply too wide. No one rear gear is right for it. At least with the 94-97 ratios, a 3.73 is adequate but a 4.10 would be ideal; but with the 93 ratios, 3.73 is borderline too much, but 3.42 would render 6th useless below about 80 mph.

I've seen all kinds of different stuff about the LS1 version but I have no personal experience with it so I'll let someone who does, if there is anyone, speak to that.

Dyno Don

iTrader: (7)

[QUOTE=sofakingdom;5589501]I pay NOT THE SLIGHTEST attention to any of those "ratings" fantasies.

Right, 93 is the one with the different (poorer) ratios. Regardless of any "ratings", its ratios are simply too wide. No one rear gear is right for it. At least with the 94-97 ratios, a 3.73 is adequate but a 4.10 would be ideal; but with the 93 ratios, 3.73 is borderline too much, but 3.42 would render 6th useless below about 80 mph.

/QUOTE]
I'm sorry but my combination defies what you are saying.
I have the 3.73's you talk about and my cars cruises at 2200 rpm's @ 70MPH, gets 20+MPG and is an absolute pleasure to drive on the street and the race track.
Anytime you put any cam with any kind of duration, 6th gear with 50% overdrive and 3.73's is borderline terrible, it has to have 4.10's at least.

sofakingdom

iTrader: (1)

Yup, I talk about em because I have em.

They're BARELY enough. 4.10 would be better.

I also have the close-ratio transmission, since that allows the motor to stay in its power band where it's happy, in ALL the gears.

Problem with the wide-ratio gears is, it's extremely hard to build a motor with a wide enough power band to run both the EXTREMELY high 1st gear RPMs that would result, and at the same time the EXTREMELY low 6th gear RPMs. The spread from 1st to 6th on the close-ratio T-56 - almost 5½:1 - is ENTIRELY wide enough. That's essentially the same as the ENTIRE useful power-producing RPM range of a typical hot street motor, 1200 - 6000 RPM more or less.

Dyno Don

iTrader: (7)

I guess I just have the right combo then, as my rpm's never drop below 4000 when I shift and my torque stays at 400+ all the way to 5100.

My son has the other trans and has a cam with 224/234 @ .050 and can't even use 6th gear (bogs down and consumes fuel) unless doing 80+ with 3.73's.

jmd

iTrader: (4)

It's kind of arbitrary. Yes, there's reason for the M28 to be rated less than the M29. In reality the headset gears are the same and that's the most critical load bearing gearset. Keep in mind they used the weaker headset gearing in the highest GVWR application (Chevy SSR LS2) albeit with other serious main & counter shaft upgrades.

There's crap like MM6 (2.66 first) boxes rated lower than other MM6 boxes or M12 boxes rated into the 400s; neither with rhyme or reason. The point is, matching gear ratios & the rear axle to the powerband of the engine is a lot more important than having the strongest heaset gears or output shaft size.

Trends you'll notice: 3.73 isn't as drivable with the MM6 gears and a carb as with EFI.

Current projects on the table for me are a GTO trans. reworked to suit LT1 clutch. A couple 99-up Camaros (different service tag than 98.) C5 and C6 Z06 boxes are upcoming work. And a 32 spline GTO I'll need to sell.


Yep. It's very close to the ideal V8 T5 ratios in a lot of combos.

calebzman

iTrader: (3)

I purchased a '97 T56 from the classifieds at LS1tech.com. That was 5 years ago to replace a broken T5 and it's been perfect for my car/combo. I'm in 6th anytime above 55mph. Small cam FTW.

1gary

In this link it talks about multi shift locations.I still don't understand if that is true only on their aftermarket trannies or on all the T56's.


http://www.tremec.com/menu.php?m=94

jmd

iTrader: (4)

The front most location usually referred to as the inspection cover is available via installing an aftermarket detent lever and on some later T56 and TR6060 models. You can't just use the cts-v lever as its shift detent setup is different acriss multiple parts.

The Magnum has a reversible shifter for two more.

The F-body has the rearmost casting location. The Mustang casting is forward some (and was used for the "aftermarket" GM T56). The Viper is different yet but is also a longer casting in total.

So is this for the van in your avatar?

1gary

I hope because I have I think helped so many guys in the other sections on engines on this forum that I don't lose you guy's input on this question.The honest answer is yes it would be for the van which is also getting a stroker 383.I really like my 5 speed shop pick-up truck and would miss the stick shift in the van.As long as I would make the conversion,I would want a 6 speed T56.

So let me say thanks so far with you guys input and hope to see it keep coming.
Oh yeah.The van is getting a Ford 9" too to try to make it somewhat bullet proof and easier to fine tune the final gear ratio by swapping center sections.

jmd

iTrader: (4)

Is the Astro shifter position (at the trans) the same as the late box-body 2WD S10? I could see it being a very viable project but wouldn't recommend the 94-02 F / Viper gearing.

1gary

No it is a one of a kind offset.My main concern is to be able to get it forward enough.I've seen where you can buy different off sets for T56's.

wulff

Mine is the 50% overdrive in 6th, with my 406 TPI and a 3:73 rear, I find it ideal!
I read in a manual transmission book that the stock T-56 is way under-rated and will take a lot more torque than claimed.
This is funny, I read when they were building a special 'sport' model PT Cruiser they put a T-56 in the prototype but it didn't make enough power to pull in 6th gear!