T56 6spd Manual Transmission install into a Gbody

Texas82GP

Just-a-worm
Supporting Member
Apr 3, 2015
7,043
113
Spring, Texas

TURNA

Rocket Powered Basset Hound
Jul 24, 2009
10,955
113
Socialist NY
I used the factory master setup and a Spec throw out bearing
 

DONBENNY1915

Not-quite-so-new-guy
May 17, 2010
9
3
Someone asked me if there was info about this so I figure this would help some people out.

Putting a T56 6spd into a Gbody is pretty simple and straighforward, not much to it, just like installing any other Transmission pretty much.

It's good to start with getting all the parts:

T56 6spd Transmission (LT1/LS1 Fbody or GTO Type)
Clutch, Flywheel, Pressure Plate, Pilot Bushing/Bearing
Clutch Pedal & Hydraulics
Shifter & Crossmember (several companies make one now for Gbodies)
Depending on what you have in the car you may need a driveshaft or work done to the current one you have if you do not want to buy a new one. It uses the standard GM 27 Spline Slipyoke

I bought and built up a low mileage (like 20k miles on it) Tremec T56 6spd Transmission. Along with it, I bought the GM LS7 Clutch Kit with ARP Flywheel Bolts., I have a 6.0l LS Engine in my car, you guys with the Gen 1 & 2 SBC just get the appropriate parts & LT1 Fbody style T56 Transmission.

Since most of these cars were factory automatic there is no factory Clutch Pedal that will work with this. You can buy one from the few people that build them, or you can build your own.

I installed the Master Cylinder on the fire wall like it would have come in a LS Fbody. Once I did this I built a Clutch Pedal using parts from an early 90's S10 Pedal. This seemed to work perfectly for the geometry and full movement of the Master Cylinder. The geometry and movement are critical in this case, it has to have full movement as straight as possible so the rod will not bind and bend.

$7 at the junkyard and a few hours of time I had a Clutch Pedal built

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I hammered on the fire wall until I got it flat to get the proper angle for the Master Cylinder

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The Fluid Reservoir was mounted on a bracket I made then bolted to the Brake Booster

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I used a longer grade 8 bolt and mounted it next to the factory Brake Pedal. I cut the Brake Pedal down so it would clear the Clutch Pedal and use the proper size Pedal Pad

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I bought the T56 and got to the shop with it, then tore it down for inspection. Everything looked pretty much new but I always upgrade them

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Parts showed up a couple days after to build it with the LS7 Clutch Kit. If going LS buy a Speed Bleeder, they are worth it

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I re-built the T56 with the upgrades and it was ready for install

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Pilot Bushing installed and LS7 Flywheel was bolted to the back of the 6.0l

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LS7 Clutch Disc and Pressure Plate installed

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Slave Cylinder with Speed Bleeder mounted on the Transmission ready for install into the car

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Once I figured out where the Transmission ended up I cut the hole for the Shifter

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After the shifter hole was cut then the Crossmember was installed into the car and driveshaft bolted up

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The Shifter was then installed and the Center Console put back together. I made the custom Shifter Plate for my SS

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Then bleed the Clutch out and take it for a drive. Nothing much to it really and it's pretty fun to row gears with..

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Quick question I just got the whole setup from a 97 lt1 trans am can I use this flywheel on my Grand Prix or do I have to get a another one someone told I had to change flywheel
 

Texas82GP

Just-a-worm
Supporting Member
Apr 3, 2015
7,043
113
Spring, Texas
Quick question I just got the whole setup from a 97 lt1 trans am can I use this flywheel on my Grand Prix or do I have to get a another one someone told I had to change flywheel
The determining factor is if the engine has a one piece or two piece rear main seal. The old two piece rear main blocks use a different flywheel than the newer one piece rear main seal blocks.
 

85montess

Greasemonkey
Oct 20, 2007
173
28
CT
I know this is going to vary depending on application, car, where you live, exact setup, etc but what would one expect to pay - roughly? I'm debating 200-4r build up or go nuts and do a t56, because that'd be fun and awesome. Also cheers on the write up.
 

TURNA

Rocket Powered Basset Hound
Jul 24, 2009
10,955
113
Socialist NY
If you live out in the country get the T56

If you live in the city get the 2004R

I have the T56 and it sucks driving it around the "city" traffic
 

ssn696

Living in the Past
Supporting Member
Jul 19, 2009
5,011
113
Permanent Temporary
The T56 will require some floor mods. It's even larger than the Tremec shown here. I tried to maintain the driveline angle, so I ended up with a pretty big hole.

Depending upon the donor source, you'll have $3K in it when you have it running. As Turna said, if you sit in traffic on I95 in Bridgeport or the Post Road anywhere, you'll wish you had no left pedal. If you will go on long road trips, the T56 will be a joy to drive.

To confuse you even more, check out the GoPro videos Built6spdMCSS has posted. The sounds alone made me want a gearbox in my Malibu. Heed the advice about the bleeder hose if you use the OEM-style slave around the input shaft.
 

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