Hey Guys, Iv'e got the funds and decided to move forward with a T56. Now that I have the C5 with that trans it seems that changing out the TH400 behind the 383 for the M6 will make her quite the new experience. I hope this isnt too winded but Im in analysis mode. I appreciate any info you can help out with! TIA!

T56 Years and Models - I know that the early versions (93-97) were different but not sure in what way. Some have Borg Warner tags. Should I avoid them? or are they ok. I have my eye on a rebuilt unit from this era. I also have seen different references like "viper" and "magnum". What is the significance of these if any?

Gear Ratios - Are they all the same in all units? I currently have 3.73 diff but also have a full 3.08 pumpkin I can put in. Any advice here?

Clutch - I'm thinking of going hydraulic here with a tilton MC although I have not done a lot of research here. Any info on clutch options would be great. If I decide to go with a Z bar do I need special bell housing, clutch fork etc?? I also need to get a pedal set. Is it ok to find OEM on fleabay or is there aftermarket set that would work better with hydraulic setup.?

Offset Shifter - Who makes the best?

Cross Member and Mount - Same

Anyone every use this kit?

http://americanpowertrain.com/i-8521...-corvette.html

again sorry for the winded post. Thanks for the help! Happy New Year!

 

Keisler has some retrofit kits where you can use your bellhousing clutch etc.

I used an LT1 F body T56 with the LTx bellhousing slave etc
Used a centerforce 700107 (pretty sure)FW and dual friction clutch setup. This mates the fw to a 2 pc rear main seal and the LTx clutch setup.
Power est around 550+- holds it just fine (and I use drag radials full time), not grabby chattery etc.
Real happy with it so far. The hydraulic clutch spoils you but the bracket and geometry HAS to be right. Keisler can fill you in. I had to make mine and went through 5 slaves lol before I got it right this was around late 90s before there were parts for doing this.

On specifics with Vette installation maybe others can pipe in put this in an A body. Best upgrade ever.

PP bolts are McLeod #1502 I belive. Dont use regular bolts on them. They make a nice bolt in scattershield, too with a block plate.

 

Here's a thread I made on my LT1 T56 installation.

http://forums.corvetteforum.com/c3-t...gs-list-7.html

If you have the money do the Viper kit. I had a low budget, so I went with a used trans and tried to keep costs down somewhat.

 

Look for a 99 and up LS1 T56,if you get the LT1 transmission you have to use the goofy LT1 flywheel and clutch setup,the conversion flywheel if you need it for the two piece seal crank is very expensive new and can be extremely hard to find used,but are out there.The early 93-94 units are weaker than the newer ones also,if you are going the used route,look for a complete swap from a Camaro or Firebird guy that wants to go auto for drag racing,they might take your TH400 as a part trade.

 

http://www.ddperformance.com/shop/pr...7cPath=107_124

 

now that is one good looking tranny

 

Thanks Guys!

Thanks! Thats is one nice looking unit, but I think it's overkill for my app @ 700ftlbs and ~$1200 more than the reman LT1 unit I'm looking at.

If I go this route is there any other disadvantage other than having to use the special flywheel and clutch? If I use 99 or later, can use old school FW, clutch, PP and manual throwout bearing?

The unit I'm looking at is a 97 rebuilt from Camaro complete with bellhousing. I'm going to keep looking at what else is out there.

 

Mine is from an 06 GTO. Good ratios for a 3.73 rear. I also use the LS style hyd throwout bearing and I did a Tilton MC. It has a large bore so the action is very quick. Not much pedal travel but it shifts very fast. I love the T56. Smooth shifting trans.

 

I bought the D&D viper/chevy trans with offset shifter, mech speedometer, chevy bellhousing plate, modified imput shaft uses stock chevy clutch, pressure plate, TO bearing, Only mod was driveshaft length and trans mount.and great ratios for your gear. It was worth it to me because I am pushing 700 HP Tq. and the swap is easy.

 

I'm not going to take anything away from the T-56 or any of its variants but You may also consider a TKO or another 5 speed. They have roughly the same spread from 1st to top gear and they weigh less and are smaller so they fit in a bit easyer.

 

OP on your question--if you use the LSx trans if has a different length input shaft....Id ask Keiseler abouthe particulars. If its a LTx youll be fine with those parts listed. No drawbacks to the clutch far as I Can tell its a real sweet setup. Pedal is light like an import.
Guessing they make a bolt in slave bracket and show you where to mount the rod on your pedal. I cant think of any downside really.
Some like the retrofit kit where they can use the old style clutch and keep their linkage old bellhousing etc. Check into it.

And ditto on the 5 spd.
6th is useable if you have a torquey/mild motor....big huge cam you need deep gears in the rear and go 75+ to use it. 5 speeds are plenty, BUT nice to have the extra. I run a 4.11 and 26 in tire...6th is nice to have.

T56 has a 2.66 first which is perfect if you can find a 5 spd with the same or similart gearing no more than 2.88 go for it.
The ones with the 3.xx first gear then a huge drop to 2nd not for me.

 

Great thread with additional links. Thanks Much!

To all, I have considered a TKO 600 but it seems I can do a T56 for considerably less $$ as they are readily available. I will do final budget compare but for some reason the reason the thought of the 6 spd with that clutch setup appeals to me. ...nothing like top end!

 

I have a hydraulic clutch on mine - 5/8" bore, attaches to the stock pivot point on the pedal arm. I drilled out the hole that normally is used for the shift rod and mounted my master cylinder there.
That said, I had to put a smaller diameter vacuum booster on my car because it was an interference fit with the clutch master cylinder. In the end I used an ebay "hot rod" dual diaphragm booster and a wilwood 5/8" bore - NOT the short one - master cylinder with a remote fill

pm me if you want the link to that part of my build.

I'd also avoid the 3.08 gear.... at .50 double overdrive 1200 rpm would be 70 or 80 mph (so pretty much useless). Also, the first gear on the GTO transmission is designed for 3.42 gears. I ran a 3.91 in my GTO, made 1st useless.... were I to do it again (the GTO was a POS and is someone else's problem now) I'd run 4.11s or 3.42s....

 

The t-56 is a great transmission right out of a camaro. I have a 96 model behind a pretty hot 427 big block with 3.73 gears. The .5:1 overdrive in 6th puts you right at 1500 rpms at 70. that 383 shouldn't have any problems pulling down the highway. My buddy has a 96 t56 behind a 427 big block with 550 hp and he road races it a lot and has not had any issues with the trans yet. These transmissions can take some abuse, most of the upgraded parts (viper and the like) are mostly hype, make sure you have good carbon fiber blocker rings on the syncro's and upgrade the billet syncro keys and heavy duty springs and it will last a long time before you have any problems.

As for the setup:

Use the LT1 stuff, master, slave, bellhousing. You will need to extend the hydralic line but you can find adapter fittings to go from the GM oring to -4 line. Mouning the master cylinder requires a little fab work but the rod will reach the stock vette clutch pedal pin and yeilds a very short smooth pedal movement.

If you have any fab skills and a welder you can make a cross-member pretty easy.

The shifter is a little interesting. I made my own stick and used the B&M ripper shifter.

For a clutch I called Dave at Spec Clutch. I've tried Mcloed, CenterForce, Zoom, etc in my camaros and non of them compare to Spec in quality. I used the stage 2 disc and pressure plate. I also opted for the aluminum flywheel. they will custom drill a flywheel to your setup so if you have the 2-pc seal crank they will just drill a blank with the correct pattern. Need to match the balance of your current flex plate send it to them and they will make sure its the same.

You will need to change your driveshaft as the t56 uses the th350/small gm trans yoke versus the large th400 yoke. Driveshafts Unlimited in Arnold MO can set you up if your looking for a quality driveshaft shop.

Here's a link to pics of the rebuild and other various things I did to install the t56 in my vette.

t56 rebuild and install photos

 

Hey thanks guys for all the tips and links. My confidence level is building quickly. I'll also have professional help and a lift available to me. (Actually I'll be the helper!)

Sounds like I'll be sticking with the 3.73. Should have a great launch and still lots of top end.

442olds, lots of good points here, and much obliged for the link. I was all ready to order centerforce but will check out the spec stuff. my motor is internally balanced so no issues there. Shifter I'm going to take my time on. I do have the means to fab some stuff but will most likely just go with aftermarket crossmember from US powertrain or somewhere. The trans I am looking at is a rebuild that comes with the camaro bellhousing. I wasn't planning to open it up. should I consider buying a cheaper used unit and get a trans expert to crack it open and replace the parts you mention? Im sure i can find someone local to do that. Thanks guys Im building my parts list. Will post it this weekend!

 

3.73 4.11 even 4.56 are great with that trans. 6th is a big rpm drop so dont be afraid of using some gear. I am using a 4.11 and a 26 in tall tire it seems perfect esp if your motor likes to rev it doesnt feel like youre shifting too soon.

I had a 350 with a 250@050 solid roller would pull 6th...the 383 with a 260@050 pulls it even better go figure BUT you do have to be going 75ish (due to the cam). I run M/T full time and havent broken it yet. I did lose a 2nd gear pin probably from the trans sitting for 10 yrs thats it.
$5 part and a few hun labor back on the road.

 

Sorry guys not a Corvette, but I installed a T-56 Magnum in my Chevelle about 1 1/2 ago and love it. It changed the whole characteristics of the car. With 4.56 gears and 6th gear, it cruises nicely at 70 mph and a little over 2200 rpm. The 5th and 6th gears are .80 and .63. It's fully syncoed, shifts like a dream; very positive and has no issues shifting at 7000 rpm. I can't remember ever missing a shift with this thing. It has the 2.66 1st gear, coupled with these rear gears and 30 inch tires, it works very well with my engine combo. It is an LS style transmission. I went with the oem mechanical clutch z-bar setup and Quicktime bellhousing. There was some fairly major floor surgery to perform along with a modified oem crossmember (see attached links).

http://www.chevelles.com/forums/show...2&highlight=56

http://s989.beta.photobucket.com/use...70774634019767

 

dosoctaves: this rebuilt trans...was it rebuilt by someone reputable or is it someone on craigslist that says they rebuilt it? I like to do my own rebuilds because i'm the only one I can blame if it blows. The trans I bought I overpaid for...the guy said he drove it and it was only popping out of 3rd. Once I cracked it open I found that they must have been powershifting every gear as the sycro teeth on 2, 3, 4, 6 and R were all ground down. i expected to see it on 3 but 6 and R. If the rebuilt trans is relatively cheap I'd be concerned that the rebuilder didn't inspect the gear side of the syncro really good. Each gear is around $100 to $124, so the costs to rebuild a t56 can go up quick, and if they just throw bearings and blocker rings at it, they might not cure the real problem which was the previous abuse.

Now I've rebuilt two t56's, a t5 (mustang), and an NV4500 (1ton chevy truck). For whatever reason the bearing set I put in my last t56 had an issue. It was the last bearing that supports the output shaft in the tail housing. Apparently there was something wrong with the rollers and it caused all sorts of havoc. Make sure you buy quality bearings. And even then that's apparently not a guarantee anymore.

Back to clutches. I had a centerforce Dual Friction in my camaro. The clutch would expand as it got hot, it would not disengage going into 1st or reverse. And was a pain to get it into gears at the track when it was under a heavy load. The camaro boards were lit up over these dang things and eventually Ceterforce started screening calls. If you mentioned a camaro or t56 they would put you on permanent hold. Its a good clutch and a lot of people have had good luck with them, but I personally like the customer service and quality I get from Spec.

A link to quality parts, Do not get the KOYO bearings, spend the extra cash for the timken's I learned the hard way even though the guy on the phone said they prefer the Koyo's.

The Gear Box

I like the service at D&D better however.
D&D Performance

 

Had good luck with the Centerforce DF so far no issues.
Would like to learn to rebuild these....have 2 T56 here. I trust no shop.
I had a 2nd gear pin go loose...took it in and told them to use hylomar on the case....of course they used cheap orange silicone and after 2 mos it leaks of course. As they say---

 

The trans Im looking at is from a private seller in Texas. He claims it has 1200 easy Miles on it since rebuild and removed to replace with AT. It looks pristine in the picks includes bellhousing and shifter, the price is right and he is offering free shipping. I have someone here in town who can help with cracking it open and inspection. I think Im going to pull the trigger on it. Im going to reach out to the spec guy's tomorrow on clutch setup. Thanks for all the pointers...still planning but getting closer on it.