T56 Retrofit Transmission

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Don't forget the FAQ

Postby vega_man_larry » Thu Nov 08, 2007 6:24 pm

I found this in the FAQ:

"3.15 How can I upgrade my 9 1/4" flywheel to 10 1/2"?
Some have reported that a stock Chevy 10 1/2" flywheel won't fit. Hayes 30lb 10 1/2" will fit: part #490-10-330, 153 tooth. A flywheel from an '88-up Camaro (153 tooth) will also work. Note: use diaphragm pressure plate if using a stiffer clutch to prevent stress on clutch cable/firewall.

Bob (venom_symbiot) writes:
"I installed a larger flywheel and clutch in mine and tossed the recessed Monza unit. Everything fit inside the factory V8 bell housing. I would suggest you take the bell housing and see if it will fit over the new flywheel and clutch assembly. If it does, your next concern will be the starter motor. If it clears the bell housing then the only thing that could possibly be a problem is whether it clears the uni-body or not. If it does contact the uni-body, it is usually a simple matter of grinding or cutting the offending material away (as mentioned in Hooker Headers installation instructions). I would add that once the material is removed, if any spot welds were also removed that you get a MIG welder and run a bead along the area to fuse the layers of the uni-body back together to retain structural integrity.

It's not as hard as it sounds, I didn't have to remove any material to clear my starter, the flywheel fit, as did the starter without any modifications. Eventually, I replaced the bell housing with a Lakewood scatter shield that I modified to accept the Monza clutch fork and clutch cable."

It looks like the 10.5 inch flywheel is a go. I'll probably go with the 3d gen Camaro.

Larry
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Postby ColinOpseth » Thu Nov 08, 2007 7:56 pm

Larry,
The 6-speed is sweet. I recommend if you go with a 4thgen you get a 94-97 unit. They're stronger than my '93-based T56 (although mine has better ratios!!!! i.e. close vs. a bit wider).

Also, a quick way to get around the VSS issue is to contact Dakota Digital. Looks like they make a box that will power the VSS with 12v, then takes the VSS output and turns a box with a speedometer drive. Pretty simple and reasonably cheap.

If your car is a 75 you should have better luck. If memory serves me right, the '75 has the largest transmission tunnel of any year.

Also, you will need your driveshaft shortened. If you're using a 700r4 the length may be the same. I think the 3rdgen guys use the same driveshaft when they swap the T56 into their slushbox cars. Just measure to be sure.

Also, I used the stock Vega clutch pedal. I prefer the hydraulics. The pedal feel is so much better. My only worry is how to run the exhaust. Man, is it tight on the driverside. Oh man. Like less than 2" between the body and the bellhousing tight.

McLeod stuff is, in my opinion, overpriced. It's high-zoot stuff.
'72 Vega with '93 Camaro LT1/M29 T56/12 bolt 3.31. 16" IROCs all around. Sanderson headers into duals with an H-pipe and Flowmasters. It's loud but at least it's faster than your grandma's Buick. pwned.
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6 speed Still in planning stages

Postby vega_man_larry » Thu Nov 08, 2007 10:34 pm

Colin,

As luck would have it my Vega is a '75. I decided to look at the ACC Custom Carpets site to see if I can find any differences in the different years carpets. ACC carries 2 major carpets with the break being the 1975 Model Year,

P/N 16669-XX fill XX with 71 thru 74
P/N 2703-XX fill XX with 75 thru 77

So those with a 71 thru 74 car are more transmission tunnel challenged. The '75 keeps the early trans mount and the 76 and 77 have the multiple choice mount that uses the forward most 3 holes for a 4 cylinder and the aft 3 holes for a V6 or a V8.

I think I still prefer the JTR tailshaft conversion as it will provide an accurate mechanical speedo output that will not require any power (the KISS principle here). I probably WILL need to get a longer speedo cable because the speedp drive output will be about 9 inches more aft and the speedo cable I have will be too short. I'll probably try to find a catalog that lists speedo cables by length.

All the 6 speed articles also recommend the LT1 tranny from '94 thru '97 and these things are now 10 years old at least so hopefully I can get a break on a good used unit.

I also want to avoid hydraulics for simplicity. I'll carry a spare clutch cable. I'm obtaining a late model ('76 thru '77) pull type without the wheel. I'll beef up the firewall to keep the oilcanning at bay. Also '76 and '77 clutch cables are still available. I bought a wheel type when I converted my Astre years ago and I bought one of the Last wheel type cables NAPA has. Most parts books erroneously list the late model cable for all years.

If I can get it all done by spring I may just do the long haul. I should cut my fuel consumption by a third, so my gas bill will be the same as years past.

More to come as I gather parts together.

Larry
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Postby bill1978v8 » Thu Nov 08, 2007 11:00 pm

One thing that I will recomend is a good shifter. The T56 is a good transmission but needs a good aftermarket shifter. The T56 in my "other" car begs for a GMM Ripshift. There is a Monza on the web that has a T56 in it. I think there is a write up about it. Colin would know a lot of the in's and out's.

Bill
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Postby ColinOpseth » Thu Nov 08, 2007 11:32 pm

Yeah, the B&M is very popular. Hurst, not so much. In fact, many guys that have an SS (came with a Hurst shifter) have pulled it out and put in a B&M. Cost is decent at about $150.

I'm going with stock right now. I did buy a shortened stick for it on eBay. The ball is right at my knee. :)

I stayed with the hydraulics because I want to have the ability to purchase off-the-shelf parts. That's my keep it simple strategy. I only hope that I never have to fully bleed that hydraulic system. Pain. In. The. Ass.
'72 Vega with '93 Camaro LT1/M29 T56/12 bolt 3.31. 16" IROCs all around. Sanderson headers into duals with an H-pipe and Flowmasters. It's loud but at least it's faster than your grandma's Buick. pwned.
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Postby greg72 » Fri Nov 09, 2007 9:54 am

Larry, what rear end gears or you running? I know that the GM b-body guys that have done this swap recommend something in the range of 3:90s to 4:10s. . Although some have used 3:73s.

Granted you are talking the difference of a 4500 # car vs a 3500 # (at best :lol: ) car.

and as Colin mentioned , many people like the gear ratios in the '93 T56s better. The 93 is rated lower in terms of torque limits than the 94-97 .....perhaps that is not too big of a deal in a lighter car.
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It's a Ford 9 Inch

Postby vega_man_larry » Fri Nov 09, 2007 4:58 pm

I am running a 2004R with the following ratios:

2.74 1.57 1.00 0.67

I want a '94 or newer LT1 T56 with the following ratios:

2.66 1.78 1.30 1.00 0.74 0.50

I have run the automatic with 3.0 rear gears with no problems. The top end is up there and I've ran the car for hours at high speed with no problem. I have ZZ430 #099 installed in the car which makes 430 HP with the GM LT4 Hot Cam. I have a stock LT4 cam in it presently but I'm thinking about pulling it out, and putting the Hot Cam back in because I don't need to meet Delaware emissions anymore. Where I live in Texas we have no emissions rules and the car doesn't need to run a cat. With the available torque that the engine can develop I can push the little Vega along quite nicely with the 3.00 gears. My rear is a Ford and I have 2 dropouts a Possi 3.50 and an open 3.00.

Larry

p.s. I have a '95 DCM Impala SS that my wife drives. It's a whole lot bigger than my tiny Vega.
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Postby greg72 » Fri Nov 09, 2007 7:34 pm

Sounds like the ideal set up ! As you point out the Vega is a lot smaller and lighter than a 91-96 GM B-Body.

And yes the LT4 Hot Cam would be cool.

After you finish the T56 install in the Vega put one in the Impala. Maybe you could get a deal on 2 transmissions. :lol:
Greg
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Check out this tranny price!!!

Postby vega_man_larry » Fri Nov 09, 2007 11:28 pm

http://cgi.ebay.com/ebaymotors/89-96-Co ... dZViewItem

Man if this is still available in January after my stock payout I'd be real tempted. Check out the price. I know people who have paid more for used.

I've bought Corvette parts from the partsladi before. Great AC Delco parts at a good price.

Larry
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Postby ColinOpseth » Sat Nov 10, 2007 2:34 am

Careful. That's a ZF. Whole different animal to the T56.
'72 Vega with '93 Camaro LT1/M29 T56/12 bolt 3.31. 16" IROCs all around. Sanderson headers into duals with an H-pipe and Flowmasters. It's loud but at least it's faster than your grandma's Buick. pwned.
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Corvette 6 speed

Postby vega_man_larry » Sat Nov 10, 2007 3:46 am

The Corvette has a shorter overall dimension because the tailshaft is shorter. I'd need to come up with a way to mount the rear of the trans, but the shifter wouldn't be so far back. I'll probably wind up with a Camaro unit because I think I can get a used one for under $500 which is more budget friendly.

Larry
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Postby ColinOpseth » Sat Nov 10, 2007 7:49 am

I have a C-beam you can hack up if you need. It came off my '84 that I'm parting out.
'72 Vega with '93 Camaro LT1/M29 T56/12 bolt 3.31. 16" IROCs all around. Sanderson headers into duals with an H-pipe and Flowmasters. It's loud but at least it's faster than your grandma's Buick. pwned.
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Postby TimMcCabe » Mon Nov 12, 2007 2:17 pm

Larry,

If you plan on using the adaptor plate so you can bolt the T56 to the Monza bell housing, you might want to check that the Monza ball stud pivot nut is not going to be in the way of the adaptor.

The T56 flange is much bigger then the original Muncie or Saganaw, so I think the ball stud nut is going to be right in the middle of things.

I don't know if the adaptor is dry, or if you need to seal between it and the trans housing. If it's dry, you might be able to machine a hole into the plate to make room for the nut.

Cheers,

Tim

PS I've had a hydraulic set up with my T5 for the last 11 years. It's worked flawlessly.. If you do need to go hydraulic, let me know, I'll give you a rundown on what I used
1972 TPI Vega T56 6 speed

Contact me for all of your Tachometer needs
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The Ball Stud

Postby vega_man_larry » Mon Nov 12, 2007 5:48 pm

I've already thought about the ball stud. I figure you'd need a relief hole in the adapter plate big enough to clear the jam nut and the end of the ball stud. The adapter plate is dry and once you add the transmission you may not be able to adjust the clutch arm pivot as the stud adjustment end and jam nut may be obscured by the tranny. If I had two engineering cut views that I could stack one on top of the other I'd be able to determine if that adjustment will be hidden. If that is the case I'll need to get the stud adjusted before I bolt the tranny to the plate. It is one area that may prove a bit tricky.

Larry
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More 6 speed swap notes

Postby vega_man_larry » Tue Nov 13, 2007 4:54 pm

Another wrinkle about the swap is the flywheel. I'll only be able to use a flywheel from 1986 thru 1992 Chevrolet that use the 10.5 inch clutch assembly. The LT1 flywheels are balance matched to the particular engine they come on. I need a flywheel that is externally balanced but not matched. All the LT1 series flywheels need to remain with their matched engine. On ebay I find the used LT1 clutch parts for sale, but I'm afraid that the specific balance of the parts will introduce some bad vibrations that may harm my engine main bearings or throw the whole driveline into some weird vibratory state. I don't know if I'm going to use a used flywheel or not. It all depends on what is available the next few months.

I have started the parts collecting process. I'm up to $120 including shipping. I'll be more specific what parts I wind up with after I make a run to the Pick-N-Pull. What I find there will determine if I buy all new parts or not.

Larry

P.S. I did score a late model ('76 - '80 H Body) clutch pedal setup. I'll rebuild it when it gets here. bad thing is I've walked away from them in the past when they were alot cheaper. The moral is if you think you may need something some day, you better get it now.
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