Your ZF6 makes noises or won't shift, what to do?

[tccrab]

Your ZF6 has problems, what are your options?

Chapter 1.

Replace or Rebuild?

Replace:
GM no longer supports the ZF6, so taking your car to local Chevy dealer isn’t all that great of an idea.
In fact, GM sold off its entire inventory of new and rebuilt ZF6’s several years ago, so your dealer would have to locate a rebuilt unit from a GM authorized rebuilder. He will of course add on a sizeable markup and a “stocking fee” so figure on paying double for the transmission. And don’t forget that the mechanic replacing your ZF6 has likely never seen a ZR1 before, so you will be paying top dollar for his “On The Job Training”. Luckily, replacing transmissions isn’t exactly rocket science, so you’ve got a 50% chance that he’ll get it right.

Most of the new/old stock ZF6’s that GM sold off would up in private hands.
I was able to track down at least 7 of the new/old stock ZF6’s during my search so they are out there, for now. 5 years from now, who knows?
The current market price for a new/old stock ZF6 runs between $1800 and $2500.
Be sure to add in at least $250 for shipping unless you are fortunate enough to locate a unit local to you. Shipping weight is approximately 220 pounds if the ZF6 is shipped in its original packing crate and pallet.

Rebuild:
ZF Industries has long since sold the ZF6 S640 product line to Rockland Standard Gear Inc. located in Sloatsburg NY.
http://www.rsgear.com (http://www.rsgear.com/)
“Rockland Standard Gear is the only ZF-certified distributor/ remanufacturer for the S6-40 6-SPD transmissions found in the 1989-96 C4 Corvette. We remanufacture this transmission for ZF and GM. Call for information on getting your unit rebuilt.”
Their current price for an exchange ZF6 is $1895 plus shipping. They give a 1 year warranty on parts and labor. There is a $500 core charge if you don’t send back your old transmission. They will rebuild your transmission, but the price will depend on what is wrong and what they have to replace.
Parts for the ZF6 are VERY expensive.

Bill Boudreau, the “ZF Doc”; http://www.zfdoc.com (http://www.zfdoc.com/) does rebuilds and performance upgrades. He’s in Cave Creek AZ, a nice little “Artsy Fartsy” town outside of Phoenix. It's where Cave Creek Chili Beer with the jalapeno pepper in it comes from. Stay away from it at all costs(the stuff is Nasty!!).
His prices range from reasonable to not so reasonable, depending on the cost of parts, whatever upgrades you might want, and the time he spends on it.
Bill is a great guy and a wealth of information. I can't thank him enough for his guidance and patience in answering all my phone calls and emails and tolerating all my stupid questions.

Other Rebuilders:
There are other rebuilders that advertize that they rebuild ZF’s. I don’t know much about them. There’s a list over on the ZR1 Net Registry here:
http://www.zr1netregistry.com/ZR1_faq.htm#44 (http://../ZR1_faq.htm#44)


The ZF6 S6-40:
http://i71.photobucket.com/albums/i159/tccrab/ZF6-Cutaway.jpghttp://i71.photobucket.com/albums/i159/tccrab/explodedview02.jpg

There are two versions of the ZF6; the “Black Tag” which was installed on 1990-’93½ model year ZR1’s and the “Blue Tag” version which was installed in the ‘1993½ -‘95’s.
Black tag units were assembled in Germany.
Blue tag units were assembled in the United States.
Black tag units are rated to 450ft/lbs torque, blue label units are rated to 400ft/lbs.
The contact ratio was increased in the blue tag units so as to reduce the “Growling” noise common to the black tag units.
The later model ZF6s do not have a Reverse Lockout Ring below the shift knob. They have a “Crash Through” to reverse that takes about 15lb of force to engage the reverse gear.

There are a few other subtle differences between the black tag and the blue tag:
The speed sensor plug is different on the blue tag.
The tailshaft does not have two holes drilled and tapped on the drivers’ side to mount the exhaust hanger on that side.Rather than finding a new plug which I’m told is still available through GM, I just transplanted the speed sensor from my black tag into the blue tag.

Luckily the exhaust hanger has two bolts on the passenger side, so no problems there. I bent the drivers’ side away from the transmission a little so as to reduce the chance of vibrating against the transmission.

The ZF6 S-40 that is in the ZR1 is nearly identical to the one in the L98 & LT1 cars with the exception of the input shaft.
The input shaft on the ZR1 transmission is 190.5mm and the non ZR1 is 159.5mm.
The good news is that the input shaft from a ZR1 transmission can be installed into a non-ZR1 ZF6 relatively easily by most transmission shops.
There were significantly more ZF6s put into L98 & LT1 cars so it’s a lot easier and less expensive to find a non-ZR1 ZF6 and swap the input shaft from your old transmission into the new one.

Stay tuned for Chapter 2.
Removing the ZF6 at home, or...
"Honey, where's the Band Aids, and while you're in the medicine cabinet would you get me the BenGay?"

[tf95ZR1]

My trans froze @ 110 mph. A testament to our car's stout behavior,
I was able to pull over. Then I could only go into reverse.
Easy to back onto a trailer to transport home.
Had to drop the drive shaft to get it off the trailer.
I opted for a built trans from Bill Boudreau (with short shifter).
He is not cheap (you get what you pay for?) but I got a great trans and an open book of information.

[cuisinartvette]

I have a customer who is an old timer, owns a local trans shop that rebuilds all kinds of ZF trannies and is familiar with the Vette ZF. Very reasonable, too.

I have no doubt BIll knows his stuff but 3500-4k for a rebuild, no way Id pay that. To each their own though.

On bringing him a new ZF and swapping parts to rebuild..He does keep 100% of the old/unused parts. I wonder...........

[Paul Workman]

I have no doubt BIll knows his stuff but 3500-4k for a rebuild, no way Id pay that. To each their own though.

On bringing him a new ZF and swapping parts to rebuild..He does keep 100% of the old/unused parts. I wonder...........

My ZF ('95/LT1) froze at 72 mph. Last spring Bill rounded me up a new one and opened up the oil galleries (better lubrication for the reverse gear that tends to starve, according to Bill B), and matched the syncro spring tension for smoother shifting. It was $2600 shipped. It was one very smooth transmission (blue lable), I can tell ya that.

That transmission worked like a charm...right up to the moment I met my dream car...the Z. Now I have a black lable ZF which seems to whine more (in low gear especially) than the blue lable one did.

Bill had the new ZF on hand, and I chose to go that route b/c he quoted a rebuild price that was actually higher than the new price, even with the modifications.

Bill expensive? Compared to what (I guess)? Bill specializes in our ZFs (among others) and gets to see them on a daily basis. This affords him a level of hands-on expertise that a general mechanic shop doesn't see. He's learned some very useful nuances w/ regard to dealing with the ZF's common failures, and ways to "harden" them when someone wants to pass some serious (500+) hp thru one.

I shopped my ZF around to some local speed shops/transmission specialists and compared pricing. Bill's $$ was comparable, except for the shipping was extra. I opted to let Bill B do mine - paying for some "tricks" and peace of mind having an expert doing the work brings.

Hopefully, I learned enough from Bill to keep me from breaking my "new" ZF on the Z. Was it worth it? I like to think so. I was certainly impressed with the performance and smoothness!! That's worth something.:)

P.

[GOLDCYLON]

Bill expensive? Compared to what (I guess)? Bill specializes in our ZFs (among others) and gets to see them on a daily basis. This affords him a level of hands-on expertise that a general mechanic shop doesn't see. He's learned some very useful nuances w/ regard to dealing with the ZF's common failures, and ways to "harden" them when someone wants to pass some serious (500+) hp thru one.

I shopped my ZF around to some local speed shops/transmission specialists and compared pricing. Bill's $$ was comparable, except for the shipping was extra. I opted to let Bill B do mine - paying for some "tricks" and peace of mind having an expert doing the work brings.P.


Bills a good guy and his price is fair. You get what you pay for. I have all the records on my Z from the previous owners. In my 91s history it went through 4 transmissions that were replaced under warrenty. The previous owner went to Bill and had this transmission installed 6 years ago. Its still going strong. It was B&B and Cyro gear treated. I think Bill has picked up some knowledge along the way. Again you get what you pay for. GC

[Z Factor]

Your ZF6 has problems, what are your options?

Chapter 1.



Nice & informative write up worthy of reputation points. :thumbsup:

:cheers:

[ZR1Vette]

For one who is still learning about the Z...this post is excellent and helpful..thanks for doing it :icon_thum
Michael

[cuisinartvette]

Im not saying its not worth it, Im sure his rebuilds work as good as possible.
My post is based on getting a recent quote for $4000 . :jawdrop:

[FU]

Billy has done a super job on the ZF6 that he did for me that is now in the 440. I'll be sending him another black tag to do as a back-up trans. I'm VERY hard on the transmission and clutch.. the power helps out a bit also. Gotta learn to drive that power a bit better.

Is it worth it ??..............you betcha !!


Oh and hat's off to Tom C. for a great post :thumbsup:

[GOLDCYLON]

Oh and hat's off to Tom C. for a great post :thumbsup:

:cheers: Good post TCs the man !

[tomtom72]

Yea, Hats off to Tom for this write up! Thanks Tom!:thumbsup:

I have some things I've been wondering about with reguard to our zf6 box.

It seems to me that the #1 source of failures can be traced to our hydraulic clutch system not being 100%. I think we all are aware of this one & the recent GM quality control issues with repl. parts....beware & be carefull!

Also it seems that the #2 source of failure can be traced back to this "reverse gear" lack of adequate oiling. Anyone have any info that they would like to share as to 'what exactly is this issue'??? As I understand it this issue relates to the fact that 6th & rev share 'something' and it gets very little lube if the trans is in 6th at high speeds? This lack of oil leads to a welding of 6th to the (?) shaft and locks up the trans??? I guess I'd just like some light thrown on this issue, ya know what not to do or what to do to prevent this, short of rebuilding a working trans as a preventative measure. TIA!

Sorry TC, don't mean to hi-jack your thread. I just figured maybe we should have our trans stuff in one thread for easier reference use.:redface:

:cheers:
Tom

[tccrab]

Yea, Hats off to Tom for this write up! Thanks Tom!:thumbsup:

I have some things I've been wondering about with reguard to our zf6 box.

It seems to me that the #1 source of failures can be traced to our hydraulic clutch system not being 100%. I think we all are aware of this one & the recent GM quality control issues with repl. parts....beware & be carefull!

Also it seems that the #2 source of failure can be traced back to this "reverse gear" lack of adequate oiling. Anyone have any info that they would like to share as to 'what exactly is this issue'??? As I understand it this issue relates to the fact that 6th & rev share 'something' and it gets very little lube if the trans is in 6th at high speeds? This lack of oil leads to a welding of 6th to the (?) shaft and locks up the trans??? I guess I'd just like some light thrown on this issue, ya know what not to do or what to do to prevent this, short of rebuilding a working trans as a preventative measure. TIA!

Sorry TC, don't mean to hi-jack your thread. I just figured maybe we should have our trans stuff in one thread for easier reference use.:redface:

:cheers:
Tom


Let me add the 3rd most common source of failure....
Not depressing the clutch completely to the floor when power shifting.
:redface:
The PO of my Z loved banging 2nd gear at WOT to see the tires smoke. In fact, that's what he'd do so show his friends how powerful the car was.
By the time I got the car (it only had 9500 miles on it) the 2nd gear synchro was already damaged.
I tried to powershift it exactly twice and that was all it took to finish the job.
:mad:

Tom

[tomtom72]

Oh yea, every now & again I go to Bill's site and read the write up he has about that subject!

I call it the "How to properly use your zf6" instructions....my fav quote from Bill is "you have to get in the clutch pedal..and it has to bounce off the floor."

Ofcourse the amount of $ to either fix or replace or replace and fix a zf6 is a motivational factor for me to drill myself with Bill's instructions! I sooo do not want to have to do what you did Tom.....specially alone & on the garage floor!

Tom

[WVZR-1]

I believe there's substantial faulty "assumptions" regarding the "blue and black" tag ZF's. The "true blues" probably only found their way into the '95 & '96 C4's!
The difference is in the transmissions internals and isn't necassarily ID'd by the "color of the tag"! '94 cars have "lift rings" for reverse and are I believe the last of the "black tag" transmissions but the internals are not to be confused with the early 610Nm transmissions.
The build needs to be "confirmed" from the ZF tag ID on the transmissions.

[tccrab]

I believe there's substantial faulty "assumptions" regarding the "blue and black" tag ZF's. The "true blues" probably only found their way into the '95 & '96 C4's!
The difference is in the transmissions internals and isn't necassarily ID'd by the "color of the tag"! '94 cars have "lift rings" for reverse and are I believe the last of the "black tag" transmissions but the internals are not to be confused with the early 610Nm transmissions.
The build needs to be "confirmed" from the ZF tag ID on the transmissions.

The whole "lift ring" vs. "no lift ring" has nothing to do with the transmission. That particular feature lives in the shifter assembly.
You can transplant a lift ring shifter into a blue tag quite easily.

If you re-read my original post you will notice that I didn't say "All Blue Tags Don't Have Lift Rings", I quite clearly said "The Later Model ZF6's Don't Have Lift Rings".

Tom

[WVZR-1]

Ted,

Look again!

I said I believe cars thru '94 have production "black tags"! I said "true blues" were used I believe in maybe only '95 + cars and are the only "crash thru" boxes. Check and I'm quite sure you will find the ZF-047('93) box is a 540Nm box with a "black tag" and a ZF-081('94) box is a 540Nm also with a "black tag"!

The statment : "93 1/2 + are "blue tag" is faulted, it could/should state they're 540Nm boxes!

I'm not disputing a lift ring couldn't be removed! There are I believe three components that make the "blue tag" shifter unique: the lever, the cardan joint, and the primary shift shaft. These three pieces are used in only 087 & 089 builds that are in '95 + cars.


Maybe more simply stated: Not all "black tags" are 610 Nm (450 ft lbs) but ALL "blue tags" are 540 Nm (400 ft lbs)!

The build determines the trans to be 610Nm vs 540Nm "NOT THE COLOR OF THE TAG"!! I believe that to be "FACT"!!

[tccrab]

Hmmm..

You've got a valid point.

Thanks for your input.

Tom

[Aurora40]

Interesting about the tags. So if you have a black tag, assuming it hasn't been opened up, how can you tell if it's a 610Nm box or a 540Nm box? Is that rating on the tag?

[WVZR-1]

Bob,

The ZF assembly number appears on the tag. I'll post the assembly #'s that correlate to the years. That's one of the reasons I wanted to correct the information. There are many "black tags" out there and they're advertised as "black tags" (which they are) but they're not the 610 Nm boxes. I've seen some disappointed buyers!
Ted's thoughts are very widely accepted as the way it is around the various circles and if you don't own a ZF the conversation means little or nothing to you so it gets passed on. The were a couple occasions recently on the CF where fellows posted with '94 cars that had "black tag" ZF's and the general accepted response from responders were it was "likely changed". It just "ain't so"!

[WVZR-1]

From my notes on another computer I'll just stick with the LT5 S6-40:

thru '90 the part # on the tag should be 1052 000 031, '91 1052 000 035,
'92 1052 000 045 now the confusion, early '93 1052 000 045. These are all 610 Nm assemblies.

later '93 1052 000 047, '94 1052 000 081 These I believe are "black tag" 540 Nm and still have "lift ring"!

The only LT5 crash through "blue tag" '95 1052 000 087. No lift ring.

I guess I'll be embarrassed as hell if this isn't correct but I do believe it should be. I would guess there will be some crawling under the car this weekend!

-------------------------------------------------------------------------------

One other point that interests me. I never thought you could just swap a connector to use the later speed sensor in the '90 cars. I thought the '90 cars were maybe 2000 pulse DC (sq wave) and the '91 and later 4000 pulse AC (sine-wave). I don't know this to be fact but it's the way I always thought it. I went to a good bit of effort to buy an original spare from Vauxhall for a Carlton that shared the ZF transmission with the Corvette. It arrived in an original Delco package. It was a very good find and the parts guy from Vauxhall was astonished that I found him. He had NO ZF stuff and the Carlton people I've corresponded with say the parts are likely harder to find in GB than they are here.

[tomtom72]

I'd just like to thank you for adding your knowledge to this transmission thread!:thumbsup:

As an aside, I would beg your indulgence if I might ask a few questions of interest to me a 90 Z owner about the speed sensor.

Is that the part that is often referred to as a VSS in the Helm manual?

The 90 VSS is a 90 only part, right?

And it's NLA from GM?

Do you think that your source could get any more?

Sorry for all the Q's. :o
TIA
:cheers:
Tom

[WVZR-1]

Tom,

I based my thoughts regarding the VSS on the fact that a '90 car shares the CCM/BCM with an '89 car and I thought those early TPI cars were 2000 pulse. The CCM/BCM changed in '91 along with the VSS's and those I believe are 4000.
The VSS I received from Vauxhall was the only available and I believe the fellow worked hard trying to find me another one or two. I didn't need it but purchased as spare.
Something just came to mind and I mean "just", usually the speedometer looks for the signal from the ECM with most early GM cars. Maybe the speedometer might see a 4000 pulse but I expect the CCM/BCM still wants to see something else for the odometer. I sure don't know but I'll stick with my thoughts for now!


-Dave

[tomtom72]

Thank you Dave for your sharing of all this info. I'm not fluent enough yet in all this electronic stuff to actually grasp what you are explaining. Beyond the central idea that there was a change made, and that the 90 VSS is specific to the 90's car.

I suppose that if a 90 vss went bad you would be at the mercy of the aftermarket. I recall trying to buy one as a spare from my local chevy dealer and they said it was nla.

Thanks again for your sharing the light!

:cheers:
Tom

[tccrab]

Wow.
From all this talk about the speed sensor, it looks like I did the exact right thing (by accident) by replacing the speed sensor in the 540Nm blue tag with the one out of my '90's 610Nm black tag. This would explain why the plug was different.

I had called a certain ZF6 Doc about that different plug and he told me I could order a plug or a harness from GM. He didn't mention that the newer style speed sensor wouldn't work in my '90.
:icon_scra
All of this info is *really good*, it should be saved somewhere over on the Registry Site, maybe in the Technical stuff?
ZF-Factor? Could you cut and paste this stuff and add it to the FAQ's or somewhere?

[tomtom72]

Hi Tom,

I figure your idea about a "reference" thread is great. That's why I posted what I've heard about the things that affect our transmissions. I figure if we get enough participation we can collect a nice bit of knowledge and then edit it to make sure we have all solid info, bassed in fact & not rumor. We should add in a solid "how to", and then condense it and save it as reference material?

JMHO:mrgreen:
:cheers:
Tom

[tccrab]

Chapter 2

Removing the ZF6 at home...

Let’s start at the beginning.
A few months after buying “Girlfriend” I made a rude discovery during my first attempt at power shifting into second gear.
Wide straight open country road, nobody around for miles, I hear myself saying “Let’s see what she’s made of”.:D
I launch at around 2500rpms, my BFG F1’s let loose and then start to grab. I distinctly remember thinking to myself, “Well, there goes $20 worth of tire”.:wave:
When the tach needle goes nearly vertical, I grab the shifter, lift my right foot slightly, jab my left foot down and pull hard on the shift knob. I feel the shifter slip out of first and then almost hesitate as it seems to hit something as it tries to go into second. My right hand vibrates and I hear a loud grinding noise. I panic, lift the gas pedal and try to stick it into third.
It won’t go. The shifter feels “slushy”, the gears don’t want to engage.
I wiggle the shifter, push the clutch in a few times and finally it goes into third.
After I get home I call Bill Boudreau, ask him if I “Screwed the Pooch”. He tells me it will need ‘fixin but if I treat it right and don’t bang second gear it will probably last a little while longer.
Fast forward four years. A beautiful sunny Sunday. Wifey and I take “Girlfriend” out for a drive. We spend a couple hours cuisin, enjoying the early spring. The secondaries never open the entire drive (wifey… well you know…).:rolleyes:
We’re stopped at the stop sign just down the street from the house. I push in the clutch and…
It won’t go into first gear. The shifter feels “slushy”. It almost seemed like something is in the way preventing me from engaging first gear. I try second gear, same thing.
Crap.:mad:
I run it through the gears, clutch it a few times, and then in frustration just jam it into first with a loud “Clunk”. I limp down the block in first gear and carefully pull it up into the garage.
A little while later I go to push it forward in the garage so that I can get it up on Jack Stands. I put the shifter in neutral and release the parking brake. I shove on the side of the car.
The car does not move.
I rock the car back and forth and I can feel that the car is still in gear.
I recheck the shifter. It’s in neutral. The transmission however, is still in gear. I’m able to get it out of gear later by shifting through all the gears, banging on it and cussing.
Up on Jack Stands she goes.

I get on the phone, call up JeffVette. I ask him, is this something I can do at home? I can still hear him laughing. He tells me that he's doing a transmission a few weeks later and if I trailer it up to him, he'll do it for me. An intriguing offer, I must admit, especially after laying under the car and asking myself if I was nuts for even thinking about doing this at home.
But, hey, what the heck. I'm an idiot, and I've got tools. (hey, that sounds like something "Tim the Tool Man Taylor" would say).:mrgreen:

To be continued…
Chapter 3.
Removing the ZF6 at home, or...
How do I get the sardines out of the can without ruining the can?

[tf95ZR1]

Hey Tom!
I did the same thing at home. With car on jackstands, I removed the ZF6.
My biggest surprise was how darn heavy the trans was! Be careful!
Good Luck,
Ted

[Jagdpanzer]

TomC
Where is chapter 3??

[tccrab]

Chapter 3.
How do they put so many sardines in such a small can????

The car needs to be at least 18 inches off the ground either on a lift or with jack stands under the 4 corners.
Getting your Z off the ground is a lot harder than it sounds. The front end is too low for a standard floor jack to fit under, and there really isn’t anywhere under the back to lift the car with a standard floor jack.
I bought a nice expensive pair of ramps to drive the front of the car onto, but couldn’t use them because they slipped on my epoxy painted garage floor.
I made my own ramps by cutting up some old 2x6’s into three pieces, 24 inches, 18 inches and 12 inches and screwing them together with wood screws. Driving the front wheels up onto them gave me enough clearance to fit my floor jack under the front of the car. I jacked up the front end high enough to get tall jack stands under the lift points just behind the front wheels.
The rear end was more of a challenge, there’s really no place to put a standard floor jack onto the rear end and no place on the frame that’s readily accessible. My neighbor welded me up a piece that fit into where the cup on my floor jack would normally be that fit under the pumpkin. A ZR1 looks funny when it’s 24 inches off the ground. It also looks very unsafe. The best place to put jack stands are the lifting points just in front the rear wheels.
http://i71.photobucket.com/albums/i159/tccrab/100_1012.jpg
-disconnect negative battery cable
-put shifter into 3rd gear
-remove shift knob (this is a lot tougher than it sounds, see Appendix A)
-remove console top & shift boot
-release parking brake
-remove exhaust
-drain transmission oil
-support engine with separate jack (I used a ¾ inch thick piece of plywood to distribute the weight across the entire oil pan)
-support transmission with separate jack ( I fabbed up trans cradle out of a ¾ inch piece of plywood and some 1x2 wood pieces)
-remove c-beam bolts (See Appendix B)
http://i71.photobucket.com/albums/i159/tccrab/cbeambolts.jpg

-remove clutch slave unit, carefully tuck it out of the way where it won't be banged around.
-remove c-beam e-brake wire clip at rear of c-beam
-slide c-beam forward until you just clear the e-brake cable in the back, lower transmission/engine so that you can slide the c-beam back and down, there will be a lot of pushing and shoving, grunting and groaning, but it will come out.
http://i71.photobucket.com/albums/i159/tccrab/ZR1045.jpg
-remove u-joint bolts; mark u-joint caps and bolts so as to put them back in exact same place (I used white out and felt tipped marker)
-remove drive shaft taking care not to dislodge u-joint end caps (I put a piece of duct tape around the entire u-joint to keep them in place)
-remove speed sensor, backup light & CAGS plug and tuck wiring out of the way
-unbolt transmission; leave two bolts in finger tight
-let engine down until the shifter just clears the opening
-remove last two transmission bolts while holding transmission in place
-Carefully slide transmission out; do not pry between trans and bell housing, you do not want to mar the surface between them.
-unbolt cat shields from sides of bell housing
-unbolt front inspection plate
-remove shift fork ball cover (reverse thread)
-loosen ball (reverse thread)
-wiggle shift fork back and off of throw out bearing
-unbolt and remove bell housing
-mark pressure plate and flywheel to make sure you get it back in the exact same place
-unbolt and remove pressure plate
-inspect/replace pilot busing as necessary
-Clean and inspect pressure plate & flywheel

Now you’re ready to reinstall the transmission. Just reverse the process and you’re good to go.



Appendix A.
The stupid !@#%^$#& shift knob
Gently pry the shift pattern insert out of the shift knob. A small screwdriver does nicely. You can put a piece of tape on the edge of the leather to keep the screwdriver from marring the leather (thanks to Johnny Phrogs for the pics)
http://i71.photobucket.com/albums/i159/tccrab/shifter1.jpg
Now comes the fun part.
There’s a metal wedging key that locks the knob to the shifter that has to come out before you can unscrew the knob. In the next picture you can see that Johnny used a pair of pliers to grab the thing and yank it out.
It looks deceptively simple, but it isn’t.
http://i71.photobucket.com/albums/i159/tccrab/shifter2.jpg
I gave up on the pliers and started hunting for something that I could wedge under the edge and pry it up.
Inspiration hit and I found some roofing nails. The head on a roofing nail is very thin and is very strong. I slid the nail head under the edge and gently rocked the wedging key.
Up it came.

Appendix B:
C-Beam Bolts
It is a major PITA to get a wrench on the c-beam nuts on the transmission end. There is absolutely no room to get your hand up and over the c-beam and transmission. Everything must be done by feel.
My hat is off to anyone who put the original nuts back on the c-beam bolts.
I highly recommend Bill Boudreau’s (the ZF Doc) “C-Beam Plates” they make the job a lot easier.
http://i71.photobucket.com/albums/i159/tccrab/cbeamplates.gif
There is a really nice write up on them over at the Corvette Action Center:
http://www.corvetteactioncenter.com/reviews/showproduct.php/product/27
Bill has a very nice write up on transmission removal on his site:
http://www.zfdoc.com/transmission.htm
TomC
"Crabs"

[flyin ryan]

i've just recently pulled the ZF out of my Ruby Zee. wasn't that bad, went pretty smooth & quick
http://i228.photobucket.com/albums/ee142/flyinryan_ZR1/IMG_0995.jpg

[flyin ryan]

http://i228.photobucket.com/albums/ee142/flyinryan_ZR1/IMG_0996.jpg

[flyin ryan]

http://i228.photobucket.com/albums/ee142/flyinryan_ZR1/IMG_0998.jpg

[Chris_32212]

When it comes to ZF or T56, Bill at zfdoc.com is the MAN!!! he rebuilds them for almost any application. his email and phone are listed on his page and he answers almost everytime i have a question about my trans and he always has the answers i need. he had a slave cylinder for my car when nobody else except white racing did but bill was a third of the price. i broke my clutch fork (seriously, i have pictures of it. lol) and he had the pivot stud i needed and got me the info on where to get a new fork. quick shipping and really awesome guy to work with. :thumbsup:

Chris