Putting a T56 in a G-Body

Send me an email at craig [AT] shiftn6 [DOT] com if you see any errors or have anything to add.

Deciding on what trans to use

• OEM T56 - 94-97 is the prefered trans, the 93 is weaker. No mechanical speedo hookup. Probably the cheapest route however.
• Aftermarket T56 - Can use an aftermarket scatershield. Can use hydraulic or mechanical clutch. Has a mechanical speedo output. Sort of expensive however.
• Richmond 6 - Very expensive! Dont know the torque rating of this trans. Cant really think of any real benfits of this over a T56!

Locating a trans

For an aftermarket T56, the best place ive found is Liberty. (313-278-4040)
For an OEM trans you can try Billy Grahams Camaro/Firebird salvage at http://www.billygrahamscamaro.com/
For a ROD 6, maybe Summit or Jegs. I dont know who has the best price. This trans costs almost $3000!

Hydraulic or mechanical?

This sort of depends on preference and maybe budget. If you go with a hydraulic clutch with the aftermarket T56, you will need 3rd party components. I am not aware of any way to use mechanical linkage with an OEM T56, however maybe Mcleods universal bellhousing would allow that. Its mostly preference, however there are a few benefits of hydraulic. Little to no maintenance, more header clearance, simpler setup. If you are budget minded and going with the aftermarket T56, then id go with a mechanical setup. I wont go into detail about the mechanical setup because I just dont have any experience with this setup. Look at the links section for a few good links on that.

Hydraulic clutch set up

This section is divided into two sections, one for the aftermarket T56 and one for the OEM.

OEM T56 - You can either use a stock LT1 bell and the stock style master and slave cylinder, or Weir Hot Rod products makes a new bellhousing and supplies a hydraulic T/O bearing. If you go with the F-body components, get a 93-97 slave/master cylinder set up as it comes with a braided line and is much better than the 84-92 setup.

Aftermarket T56 - The only EASY way that I found to put a hydraulic clutch into a G-body with this trans is to use Mike Forte's modified McLeod bellhousing. This comes with a CNC 7/8" slave cylinder which attaches very closely to the bellhousing and uses a billet fork as well. I would NOT recommend trying to use a 83-92 f-body bellhousing because the slave cylinder ends up being in about the worst position for header clearance. This set up may work if you dont mind running shorty headers. Now, if you go the route I did I highly recommend that you buy the McCleod F-body master cylinder since it is a bigger bore and will provide more slave travel. I honestly dont think the smaller OEM f-body master would provide enough slave travel for proper clutch disengagement with the Forte/Mcleod bell and slave.

You will also need to buy a fitting from Mike Forte that goes into the M/C and provides you with an AN-4 connection. An OEM hydraulic line cannot be used here since it will NOT connect to the slave in any way! GM, in its infinite wisdom made some goofy fitting to connect the slave and master together. Mike custom makes a fitting just for this problem, give him a call!

When you make your clutch hose, make sure you buy teflon hose that is approved for brake fluid. Summit and Jegs carries the correct hose. Also, buy the correct fittings for teflon hose as this isnt your standard -4 line!

Clutch master cylinder

I recommend using the Mcleod 139001 master cylinder. It seems like a good upgrade over the stock f-body unit in either case and I would consider it a requirement if you go with the same setup I have! Figuring out where to mount the master cylinder is quite easy thanks to John Bzdel who supplied me with this pic. I highly recommend drilling the hole that the master cylinder body slides through and then when you are happy its located correctly mark and drill the two mounting holes.

Clutch

I chose a SPEC stage 2/3 hybrid clutch. So far it seems very streetable and I am happy with it. For the street, the only other good alternative would maybe be Mcleod. Im not a big fan of RAM,Centerforce,Zoom, etc. There might not be anything wrong with these guys, but id be concerned using them if you are putting out any decent power.

I should also say that with the stage 3 pressure plate and the fact that the clutch fork is probably a good inch and a half shorter than the stock unit, the clutch pedal is a bit on the stiff side! I'll go out on a limb a bit and call it acceptable for everyday driving, however if you dont absolutely need the stage 3 pressure plate, you may want the stage 2. Im assuming it would be better, not sure though.

Flywheel

SPEC also has about any flywheel you would need. Theres a few variations given if you are running a 1 or 2 piece main and if its internally or externally balanced. If you are having trouble finding a flywheel, give SPEC a call. I highly recommend these guys!

Pedals

Hydraulic - This is easy. Simply buy a clutch pedal from John Bzdel and bolt it to your stock brake pedal. You will need to trim the brake pedal pad a bit for clearance. Just use the new clutch pedal as a template.

Mechanical - You will have to locate a clutch pedal from a 3 or 4 speed G-body. There are several places that make reproduction pedal set ups.

Pedals - Misc.

For a starter safety switch, if available you can easily use a stock switch from a 3/4 speed G-body. I didnt have a relaible one available to me so I used a lever activated microswitch. Click here for a pic of my starter safety switch.

I fab'ed up a clutch pedal stop so that I wasnt bottoming out the master cylinder when I jam on the clutch. Click here for a pic. This pic also shows one brace that runs from the pedal pivot bolt to one M/C bolt. This is a mid 80's 5 speed f-body part modified. Click here for a pic of the other support brace.

Crossmember

Keep in mind that the trans mounting pad for the crossmember sits back approximately 2" on the aftermarket T56 as compared to an OEM T56. The crossmember that www.crossmembers.com sells was designed for the OEM T56. However, I used this very crossmember, all I had to do was notch it a bit. Click here for a pic.

Ive heard that a crossmember from a 2004r equipped g-body works good. Again, this is for the OEM T56 so some additional modifications would probably be needed.

Speedo hook-up

OEM T56 - Not completely sure about this one, but I am pretty sure you can get an autometer elctronic speedo that will work with this VSS. Also, I believe www.jagsthatrun.com sells a new tail housing that will give you a mechanical speedo output.

Aftermarket T56 - This is easy. You will need to order a T5 speedo housing and the correct driven gear, also a T5 part. There is also a small plate that holds the housing in and from spinning. I fabbed my own, however from looking at a 2004r I am pretty confident its the same piece! Also, im assuming a T5 part would be the same as well, although im not positive.

Electronics

OEM T56 - Theres the electronic VSS of course and not sure if there is anything else! Im assuming there is a reverse indicator for reverse lights and also the reverse lockout solenoid, however im not positive.

Aftermarket T56 - Just the reverse lights and reverse lockout solenoid. You will need to order a pigtail from GM for each. I didnt hookup the reverse lockout solenoid. All it does is block the shifter from going into reverse unless you energize it with 12v. However, you can just use a little elbow grease and easily overpower it.

Shifter boots

You will need two shifter boots, a lower and upper. For the lower, I highly recommend the 4th Gen f-body boot. Click here for a pic. For the upper I used a C5 leather boot and it turned out great! Click here for a pic.

Shifter

Seems to me that the Pro 5.0 is the hot shifter for these transmissions. However, the aftermarket T56 comes with a decent shifter and ive stuck with that so far. All that is needed is a shifter knob.

Headers

With the setup that I run(Forte bell and slave cylinder) I have awesome header clearance. I could probably run any header I wanted! I am running full length Dynomax and only had to trim the bellhousing a bit to clear on the passenger side. For an OEM T56 using the LT1 bellhousing, im pretty sure header clearance is just as good. For a mechanical clutch your options are a bit more limited. I know the Edelbrock TES headers work and ive heard from several people that the Flowtechs work as well.

Links

www.fortesparts.com - Supplies the modified Mcleod bell, billet fork and slave cylinder.
www.weirhotrodproducts.com - Supplies a new OEM T56 bell and hydraulic T/O bearing.
http://www.chevyhiperformance.com/techarticles/48446/ - Article talking about the Weir solution.
www.jagsthatrun.com - Supplies a new tail housing for an OEM T56 to eliminate the VSS and provide a mechanical speedo output.
http://www.ddperformance.com/GM%20T56.htm - D&D performance, T56 specialists.
http://garage-scene.home.att.net - Excellent resource for manual tranny G-body swaps.
bzdel@earthlink.net - John Bzdel...He makes the hydraulic clutch pedal for G-body's.

Possibly useful facts

The slave cylinder included in Mike Forte's kit is made by CNC and the P/N is CN305-G, it has a 7/8" bore and 1-1/8" stroke. However, at least an additional 1/8" can be obtained by removing the inner snap ring which Mike already does. These are rebuildable as well, rebuild kit P/N CN942

The McLeod M/C bore is 13/16" vs. the stock f-body M/C bore of 3/4". This translates into more slave travel and a stiffer pedal.

The required throwout bearing travel for proper clutch disengagement for the stage 2/3 SPEC clutch is 3/4" This tranlates into approximately 1-1/4" of slave travel required.

Parts list

Part	P/N	Manufacturer	Supplier	Status	Price
T56 Trans	1386-000-011	Tremec	Liberty(313-278-4040)	Received	1,875.00
Forte/Mcleod bellhousing with fork/slave cylinder	N/A	Mcleod/Forte	www.fortesparts.com	Received	569.00
Billet aluminum 153 tooth neutral balance flywheel	SC45A	SPEC	SPEC
10.5" Stage 2/3 clutch	SC193H	SPEC	SPEC
Clutch, flywheel, throwout bearing package		SPEC	SPEC	Received	668.00
Polished aluminum shifter knob	N/A	Mike Forte	Mike Forte	Recieved	35.00
Jegs mini starter (adjustable, 153/168 tooth)	10001	Jegs	Jegs	Received	117.39
Gforce T56 Crossmember	RCT56	Gforce	crossmembers.com	Received	259.99
Frame extension for 78-83 G-body's	FE100	Gforce	crossmembers.com	Received	59.00
Pigtail for backup lamp	12085485	GM	gmpartsdirect.com	Received	9.56
Pigtail for reverse lockout	12101857	GM	gmpartsdirect.com	Received	9.88
1993-2002 F-body lower shifter boot	10267518	GM	gmpartsdirect.com	Received	20.60
Clutch/Brake pedal pad x 2	1256202	GM	gmpartsdirect.com	Received	4.38
Custom clutch pedal	N/A	John Bzdel	John Bzdel	Received	160.00
Speedometer housing	345215	GM	gmpartsdirect.com	Recieved	10.45
23 tooth speedo gear	3860346	GM	gmpartsdirect.com	Recieved	3.14
Master cylinder adapter fitting	N/A	Mike Forte	Mike Forte	Recieved	45.00
5 quarts of synthetic ATF	N/A	Royal Purple	Local Speed Shop	Received	39.95
Poly trans mount	3-1108G	Energy Suspension	Local Speed Shop	Received	20.97
Flywheel bolts	912	Mr Gasket	Local Speed Shop	Received	7.50
Pressure plate bolts	910	Mr Gasket	Local Speed Shop	Received	4.95
Shorten/Balance driveshaft, 2 new spicer u-joints, and new yoke	N/A	N/A	Elgin driveline	Done	201.05
2 AN-4 fittings, 2' line and adapters	N/A	N/A	Local speed shop	Received	45.12
C5 Upper shift boot	10340226	GM	gmpartsdirect.com	Recieved	36.92
Adjustable clutch master cylinder	139001	Mcleod	Summit racing	Recieved	241.87
Total:					4444.72

Thanks to...

Thanks to the following people for graciously answering many questions and ultimately making this swap much easier for me!

• Mike Donovan
• John Bzdel
• Glen Brewer
• Rob Patton
• Jeff Myers
• The gang over at the maliburacing.com forums
• The gang over at the g-body.org list
• And anyone else I missed!