T56 Retrofit Transmission

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Postby TimMcCabe » Fri Apr 04, 2008 9:08 am

Hi Larry,

Is the spline on the ZF output shaft long enough (deep enough) to allow proper movement of the slip yoke?

With the IRS and torque arm, the Corvette does not need to worry about the yoke bottoming, but the live axle might be another story.

Also, will you have to run the duel mass flyweel?

Cheers,

Tim
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ZF 6 speed

Postby vega_man_larry » Fri Apr 04, 2008 10:31 am

I can run another flywheel and clutch and pressure plate. Some of the Corvette guys run the F body setup, and I'll probably use the flywheel for a 1 piece crank. I've got to read through the Corvette forum, but the dual mass was designed specifically for the LTx series engines. I also was looking at the slip yoke and it looks like it will work. I should have enough room for movement of the driveline. I'vegot a few questions I've sent to the ZF Doc and I'm hoping for a favorable response. It looks like I can bolt in a speedometer gear that will allow me to run the stock speedo. I also have sketched up a removable rear transmission mount. I still need to get a few more parts and put it in the car to figure that one out. I make fullsize cardboard templates and use that as my pattern.

Larry
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Postby megavega » Fri Apr 04, 2008 1:18 pm

For actually driving a car like pro touring and power tours, the dual overdrive is priceless for gas MPG and top speed, at $4 a gallon for junk gas its definitely the right way to go.

Larry, I see you have thrown out all your original ideas and budgets from page 1,....LOL this pretty much happens to any project doesnt it.
1972 hatchback, 28,000 orig miles, 427BBC/twin T4 turbo's/T56 six speed/big wheels, lowered down pro touring style-work in progress....

1973 vega wagon-under the blue flame knife.
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Postby greg72 » Fri Apr 04, 2008 2:37 pm

Larry, I am so thankful for all of the work you are putting into this and equally important if not more importantly, your willingness to share the information!

It is invaluable to me as I am going to be swapping in a manual 6 speed OD trans in at least one of my h-bodies!

Thanks again!
Greg
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More data

Postby vega_man_larry » Fri Apr 04, 2008 11:46 pm

I found this data reasearching the ZF swap. I probably wouldn't have gone this way but the deal fell into my lap. Most T56 swaps would cost alot more. Employing used Corvette parts will drop the cost of this swap in my case. I may be able to do this for under $1000! I imagine the 6 speed knob in the car. Here is what I found:

"A "Blue Tag" ZF6 was used from sometime in 1994 until 1996. It was produced in the United States, and has
a Blue service tag. Re-angled gear machining lead to more quiet operation. The collar on the front has been reduced
to 1.311" so that a nylon insert could be pressed into the Throw out bearing. (To reduce wear, I'm told). Therefore,
your clutch disc will need to be specific to the transmission you have."

I have learned that the "Blue Tag" I have is rated around 400 ft lbs of torque. It's good I found the "quiet" one.

"1) If using a Singlemass T56 flywheel out of a 93-97 V8 Fbody (OEM# 10125379), you can use a Fbody sprung hub clutch disc (OEM #12551309),
but must use the propper ZF6 pressure plate for your transmission. Additionally, the flywheel must be resurfaced .090" for clearance
with the clutch fork to bell housing. This will only work on 1986+ motors with 1pc rear main seal!"

My engine has a one piece rear main seal. I will use the F Body single mass flywheel. I'll get a used one and have it resurfaced with the necessary .090" of clearance.

I also need the pressure plate that is for the "Blue Tag" ZF transmission (see above). I'll get one from "thepartsladi" on ebay. I'm going stock as I'm interested in milage.

Because I have the hydraulics I'll probably go that route. I plan on machining an adapter mount that will bolt to the end of the transmission case. It will have ears machined on it. The necessary C section mounted on an inverted T (a C with wings at the bottom). I can sandwich some polyurethane sheet and bolt this to a fabricated crossmember. I'll put in subframe connectors and bolt the crossmember to it.

I still need to figure out the speedo drive, but I think I can adapt a manual drive to my application. If I'm sucessful that will solve the final piece of the puzzle. This project has taken some twists and turns that's for shure.

Larry
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I should rename this the Corvette ZF 6 Speed Swap thread

Postby vega_man_larry » Sun Apr 06, 2008 6:39 pm

Well the ZF swap continues. I just added a Corvette clutch pedal assembly to the mix. I'll do a mixing and matching of components, and the Corvette setup has the correct relationship to the clutch master cylinder which I'll maintain. I'm gonna go hydraulic clutch. I've been in PowerTour lines for a long time and I'm getting old so the less pressure on my knees the better.

What is funny is that I can pick up a new flywheel, pressure plate and clutch from Carolina Clutch for about TWICE what I paid for the transmission! I'm going to check some junkyards for the LT1 Camaro flywheel and have it machined. They want $400 for a new billet steel flywheel that needs no machining. I need to run a Corvette pressure plate and I'm using the 11 inch clutch. I run an early LT1 Corvette starter so everything should work.

As soon as I get the Corvette clutch pedal I'll work an getting the brake and clutch pedal combination worked out so I can have it installed in the car.

It's funny how all this changed when I got a steal on the tranny.

Larry
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Postby gt350fme » Sun Apr 06, 2008 7:09 pm

Should be worth every penny when its all done, enjoy the Journey!
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2 more problems solved

Postby vega_man_larry » Tue Apr 08, 2008 7:56 am

The ZF transmission has the CAGS (Computer Aided Gear Shift) system installed. It also has an electronic speedometer drive. I need a mechanical speedo drive and I need to get rid of the CAGS system. I sent my queries to the ZF Doctor and this is his reply:

Hi Larry,

> What should I do about CAGS? I still have the solenoid(?) on the
> transmission. Can this be removed and plugged?

Absolutely, use a M20x1.5 screw plug to cap the hole. If you don't have a wrench to remove it, take a grinder to the CAGS shell and grind away the swaged crimps all the way around and smack the CAGS shell with a hammer until it becomes loose. Then work the shell off. At this point you will then be able to get a pipe wrench to grasp the base solidly to loosen. Remove the solenoid assembly along with the actuation pin and spring. There is no risk of parts falling into the transmission during this process. If you can't source the screw plug locally, we have the M20x1.5 hex drive screw plug with same 10mm allen drive size as the plug next to it for $15 plus $5 S&H.

> Do you know of a way to drive a mechanical speedo instead of using the
> speed generator setup?

We have a device that will take the electronic signal from the transmission (4K pulses/mile) and mechanically drive the speedo cable. This device will handle any ratio differential based on settings of the pin switches within the Electronic Ratio Adapter portion of the device. Cost of this device is $310 plus $12 S&H. It is a high quality device that is deffinately worth the money spent.

For both items, figure on $325 plus $12 S&H.

We no longer accept payment by credit card or paypal.

Please send check payable to:

ZR51 Performance
5612 E. Almeda Ct.
Cave Creek, AZ 85331

Best regards,
Bill Boudreau
ZR51 Performance
(602) 319-6575

P.S. We are working on designing a bell housing for installing a ZF S6-40 transmission to an LS(x) motor if you might be interested. The new LS crate motors are putting out some impressive numbers.

This data may help others make their decision. Oh I also noticed that Jags That Run has removed the mechanical speedo drive adapter from their website. Too bad for the T56 crowd. It was priced around $350 with tailshaft exchange.

Larry
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for those inquiring minds

Postby vega_man_larry » Tue Apr 08, 2008 8:19 am

There was a question asked earlier in this thread about the yoke used with the ZF transmission. The ZF6 uses a Turbo 400 yoke and a Turbo 400 seal at the tailshaft.

Larry
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More Tech Data

Postby vega_man_larry » Wed Apr 09, 2008 8:51 am

I spent yesterday after work cleaning parts. It is amazing how much the Corvette vendors want for this stuff. I cleaned everything but the bellhousing and tranny. The bellhousing is Magnesium snd the inside is pretty dirty. I'll look for a good degreaser today.

I found a source of good tech data and part numbers. Here is the link: http://www.zf-group.com/pdf/S640.pdf I used the shifter diagrams to disassemble and reassemble the shifter. You'll notice the shims and nylon blocks with the groove need to be replaced exactly per illustration.

I've been checking junkyards for flywheels. I'll probably bite the bullet and get new as they sell the flywheels with the engines (LT1s and LT4s are externally balanced).

I have a 200R4 which i'll be swapping out. It is 27 and 11/16 inches long. The ZF is about 31 inches long so the length is pretty close. I need the boot and a few bolts but everything is there.

Larry
Last edited by vega_man_larry on Mon Apr 14, 2008 2:04 pm, edited 1 time in total.
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Postby cosvega76 » Wed Apr 09, 2008 10:25 am

Larry,

You may want to consider while you have the trans out of the car to install an aftermarket shifter. I put a Hurst in my Corvette while the trans was in, but it would have been a lot easier if it was out of the car.

The Hurst is the shifter that car should have come with. Even Teresa remarked how much better it is.

By the way, thanks for the email about the Forum. I'll keep an eye out for you.

Chuck
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More ZF part notes.

Postby vega_man_larry » Mon Apr 14, 2008 1:59 pm

I found this on the Corvette Forum. For those thinking about using the ZF. They have the transmission for sale new on ebay at $1300. The problem is finding the rest of the setup.

"TH400 rear seal, Timken #9449 (if using a used ZF.) Also, most parts stores have the ZF6 seal wrong in the computer, so don't listen to them.

backup switch connector, a.k.a. horn connector. AcDelco PT1357 or Napa ECHEC11

(5) metric M12 x 45mm transmission bolts
(odd size, get it from mcmaster.com #92820A650)

(6) standard 3/8 x 1-3/4" pressure plate bolts
(odd size, get it from mcmaster.com #92316A630)"

I'm almost there. I'm looking at clutch flywheel pressute plates. the flywheel is going to be a challenge. I can get a steel billet one for $400. I'm looking for one a bit cheaper.

Larry
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More work on the ZF Swap

Postby vega_man_larry » Wed Apr 16, 2008 9:44 pm

I found an F Body LT1 flywheel (used) and a machine shop that will remove the required 0.090 from the flywheel for clearance. I should be into flywheel less than $150. It beats the Carolina Clutch $400 unit as I do not intend to race the car and don't need a bulletproof billet flywheel anyway.

I recieved the clutch pedal parts. I'm integrating the bracketry into the late model clutch pedal assembly. I'm also integrating the forward part of the early Vega bracketry into the late model bracket to allow it to bolt up to my car ('75 last year of early clutch pedal).

The centerline of the clutch pedal pivot is moved down in the late bracketry. The early setup shares a common shaft. What this does is move the shaft down allowing the Corvette clutch master cylinder to be mounted lower missing the brake master cylinder. I'm integrating the flange where the Corvette clutch master cylinder bolts up to the Vega pedal bracketry. Using a dremmel tool I can cut the bracket where it shares a comon shaft and weld it up. It is all falling together nicely and I am maintaining the relationship between the Corvette pivot bolt, the pushrod pin on the clutch pedal arm, and the mounting surface for the clutch master cylinder. I remember reading an early article about a Camaro T56 swap into a HotRod and thegeometry of the clutch master cylinder is a nightmare. In contrast if you integrate the Corvette clutch pedal bracketry into an H Body pedal assembly it is relatively easy to maintain the same relationship because they both use hanging pedals. And I dreaded the hydraulic clutch, and the pedal setup winds up no big deal at all.

Larry
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Postby TimMcCabe » Wed Apr 16, 2008 10:51 pm

Hi Larry,

I've been looking at pictures of the ZF shifter, it looks like it is mount a few inches to the left above the output shaft

Is your tranny tunnel wide enough, or will it require a little "tweeking" to fit? The linkage lookes like it is external, can the shifter housing be relocated?

The shifter housing on my T5 is very narrow and above the output shaft, and it barely fits in the tunnel.

Cheers,

Tim
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Transmission Tunnel

Postby vega_man_larry » Thu Apr 17, 2008 1:40 pm

Tim,

The shifter is partially inside and partially outside. It has a shaft that selects the gears. the shaft is attached to the shifter and the shifter is on the left side of the tail shaft housing. I'm going to keep the shifter stock and probably do surgery to the tunnel. I'm sure the left side won't fit. I'll go find me a donor car and get the complete tunnel area and splice it in. I have a Monza V8 bellhousing and it is longer than the Corvette bellhousing, which is about an inch shorter. Both bellhousings have the clutch fork on the left side and are similar in size. The transmission assembly isn't that much longer than a turbo 350. I have two aluminum drivelines and I'll use them both to make one for the car. It's quite the adventure, I've been working every night after work on the project and solving the installation issues has been interesting.

I don't believe a ZF six speed has ever been installed in a Vega before so this should be a first.

Larry
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