Guess how I know that?
better 6 speed option
Melting Slicks
Joined: Jun 2011
Posts: 2,383
Likes: 385
From: Leland , North Carolina
If I had to do it again on this car I would have went with the TKO 5 speed because now I have to have the rearend gears swapped out to a 3:73 or 4:11. Same money less headache...
Last edited by TommyFox; May 13, 2021 at 11:57 AM.
Team Owner
Joined: Aug 2004
Posts: 21,543
Likes: 3,216
From: Park City Utah
My wife's T56, while driving ~70mph in 6th gear on the highway, lost the reverse speed bearing and took out the main shaft, reverse gear, rev synchro and all associated parts. Super cool. Does fixing the weak points it fix that?
Well...we know that ain't true, because all of us, including you, knows that Bill will rebuild ZF's. So that's one person, for starters.
The TKO ain't a great tranny either....which Tremec admits and cites that as one of the reasons that they developed the TKX.
Well...we know that ain't true, because all of us, including you, knows that Bill will rebuild ZF's. So that's one person, for starters.
The TKO ain't a great tranny either....which Tremec admits and cites that as one of the reasons that they developed the TKX.
Melting Slicks
Joined: Jun 2011
Posts: 2,383
Likes: 385
From: Leland , North Carolina
My wife's T56, while driving ~70mph in 6th gear on the highway, lost the reverse speed bearing and took out the main shaft, reverse gear, rev synchro and all associated parts. Super cool. Does fixing the weak points it fix that?
Well...we know that ain't true, because all of us, including you, knows that Bill will rebuild ZF's. So that's one person, for starters.
The TKO ain't a great tranny either....which Tremec admits and cites that as one of the reasons that they developed the TKX.
Well...we know that ain't true, because all of us, including you, knows that Bill will rebuild ZF's. So that's one person, for starters.
The TKO ain't a great tranny either....which Tremec admits and cites that as one of the reasons that they developed the TKX.
There are plenty of old guys around here who run a TKO like this guy and love them.
Team Owner
Joined: Aug 2004
Posts: 21,543
Likes: 3,216
From: Park City Utah
Good for them.
Most people rationalize what they have, so that isn't a surprise. I've had both...2 ZF-6 and 4 T56's...no rationalizing necessary.
.
Most people rationalize what they have, so that isn't a surprise. I've had both...2 ZF-6 and 4 T56's...no rationalizing necessary.
.
Last edited by Tom400CFI; May 13, 2021 at 05:37 PM.
Burning Brakes
Joined: Nov 2000
Posts: 986
Likes: 487
The TKX is supposed to be the bee's knees... Light, 600 ft. lbs. strong and doesn't need a goofy dual mass flywheel. That's my choice for my car. A ZF would probably be a much easier install, and likely not be as expensive, but that flywheel nonsense is a deal breaker for me.
But it's new so there's a bunch of hype... Time will tell.
T56... The syncros on my 400 rwhp 2001 SS Camaro were on their last legs when I sold the car, and they were known at the time for having a problem with the 3-4 shift going to 2nd and grenading the motor. That was more of a shifter problem as I understand it than a transmission problem. The F car T56 shifter (even the upgraded Hurst, which I had) SUCKED.
T56 Magnum is supposed to be pretty stout.
Then there's the "nuclear option", the TR6060.
But it's new so there's a bunch of hype... Time will tell.
T56... The syncros on my 400 rwhp 2001 SS Camaro were on their last legs when I sold the car, and they were known at the time for having a problem with the 3-4 shift going to 2nd and grenading the motor. That was more of a shifter problem as I understand it than a transmission problem. The F car T56 shifter (even the upgraded Hurst, which I had) SUCKED.
T56 Magnum is supposed to be pretty stout.
Then there's the "nuclear option", the TR6060.
Last edited by PacerX; May 13, 2021 at 06:04 PM.
Team Owner
Joined: Aug 2004
Posts: 21,543
Likes: 3,216
From: Park City Utah
So did the Y car. At least in the C6. You ever go to "No man's land", with a ZF6? I haven't. But I DID WITH MY C6's T56!
It is possibly, likely more stout that the T56, but I researched that option for my wife's Caddy when her T56 blew, thinking it would provide better shifting than the T56, but the GENERAL CONSENSUS was that it didn't.
.
It is possibly, likely more stout that the T56, but I researched that option for my wife's Caddy when her T56 blew, thinking it would provide better shifting than the T56, but the GENERAL CONSENSUS was that it didn't.
.
Last edited by Tom400CFI; May 13, 2021 at 07:52 PM.
Thread Starter
Advanced
Joined: Aug 2020
Posts: 78
Likes: 12
From: Wisconsin
I got to admit I like you guys, You actually very helpful. I do have one last question, I didn't think you needed to stay with a duel mass fly wheel on the zf, I thought it was just to keep it quieter at idle.
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Burning Brakes
Joined: Nov 2000
Posts: 986
Likes: 487
I think there are "quieter" options than the old single mass flywheels, but I hear they still have some rattle.
The first time I heard one in the early 2000's that had been converted to single mass it sounded like the transmission was filled with loose crescent wrenches instead of gears.
Le Mans Master
Joined: Aug 2015
Posts: 6,119
Likes: 1,996
From: St. Charles MO
That's true.
I think there are "quieter" options than the old single mass flywheels, but I hear they still have some rattle.
The first time I heard one in the early 2000's that had been converted to single mass it sounded like the transmission was filled with loose crescent wrenches instead of gears.
I think there are "quieter" options than the old single mass flywheels, but I hear they still have some rattle.
The first time I heard one in the early 2000's that had been converted to single mass it sounded like the transmission was filled with loose crescent wrenches instead of gears.
Le Mans Master
Joined: Aug 2015
Posts: 6,119
Likes: 1,996
From: St. Charles MO
Thread Starter
Advanced
Joined: Aug 2020
Posts: 78
Likes: 12
From: Wisconsin
so how much more can be improved on for the ZF trans? I used to work at a engine tech in R&D. I was always amazed at improvements that wouldn't make it into production do to cost or manufacturing difficulty
Team Owner
Joined: Aug 2004
Posts: 21,543
Likes: 3,216
From: Park City Utah
What would you be trying to improve? The thing is already a brick **** house....it can be shifted FAST with this stock shifter and feel can be improved a lot with an aftermarket shifter. What improvements are needed?
.
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Last edited by Tom400CFI; May 14, 2021 at 12:19 PM.
Burning Brakes
Joined: Nov 2000
Posts: 986
Likes: 487
I'll second this... I think I'd try it before I assumed it needed improving.
Team Owner
Joined: Aug 2004
Posts: 21,543
Likes: 3,216
From: Park City Utah
I hear you? But it's hard to answer when we don't know what you're actually asking for.
I'll leave this for you, from another thread, since it's pretty heavily loaded with good transmission info (EDIT: IDK why the forum broke each of those single quotes into two quotes. WTF......
and
.
I'll leave this for you, from another thread, since it's pretty heavily loaded with good transmission info (EDIT: IDK why the forum broke each of those single quotes into two quotes. WTF......
I have been abusing my ZF blacktag for 20 years. My 91 has a 464 Dart tall deck with a 300 shot of nitrous, and runs 9.70'
s@145 with the DA at 6400ft. It should run 9.60s@7000ft DA. It probably has over 1000hp and over 1000 ft/lbs tq on the spray. I dump the clutch at 5000rpm on the nitrous with Hoosier 29X13.5 slicks, and it's run 1.3 60ft times, and I have never hurt the trans. I have hurt everything behind the trans but never hurt it. I have deadhooked this on nitrous several times and still never hurt it. One thing the ZF blacktag has near straight cut gears and a 32 spline mainshaft. There are several different variations of the T56. The F body T56 is the weakest. It has a 27 spline mainshaft and helicut gears. I have seen several and rebuilt several F body T56's that either snap the mainshaft in two or twist the mainshaft. I have seen 12 second F bodies break mainshafts. The Viper T56 is a totally different animal. It still has helicut gears, but it does have a 30 spline mainshaft. So even the strongest T56 isn't as strong as the ZF with it's 32 spline mainshaft. Every spline count matters as far as strength goes. And a near straight cut gear is going to be stronger than the helicut gears. The helicut gears have less surface area for gear contact. If you physically break a trans, it's usually a gear/countergear problem, or you break or twist the mainshaft. The ZF black tag problems I have seen are synchro problems from drivers who don't know how to drive, and could ruin the synchros in any trans. But for a factory trans, a ZF has to be one of the strongest transmissions ever put in a car.
and
So I did a little investigating today and found out some interesting data about these (and other) transmissions. PART of what made me curious was this thread...the other part was learning more about the NV3500 -a trans that I'm in the middle of rebuilding. Anyway I got curious and started looking around. I found this quote from a
HOT ROD MAG ARTICLE:
"The strength of a manual transmission is related to four main design functions consisting of cluster-to-mainshaft center-to-center distance, First-gear ratio, gear-tooth pitch, and the alloy of the steel used to make the gears. "
None of that is new to me... but this data from the same article was of interest to me:
Center to center;
T5 - 77mm
T56-85mm
I knew that the T56 had a substantially larger center-center distance than the T5 had....I couldn't remember the actual numbers. Anyway, 8mm. The T56 shafts are spread 8mm further than the T5 and that is where the at least a portion of it's increased tq rating came from, over the T5. However, the ZF6 goes another 10mm further than the T56! Here is what else I found:
NV3500-85mm (same as the T56)
ZF6 - 95mm
Wow. Of the 4 main design features that HRM feels govern trans stregnth, we can now confirm that the ZF6 holds a substantial advantage in 2.5 out of those 4:
*Center to center with a 10mm larger spacing
*The cut of the gears
*FIRST GEAR RATIO (about 1/2 of T56's have a numerically higher first gear ratio than the 2.68 found in the ZF6. The remainder have a similar 2.66)
The final design feature listed in HRM; the make up of the metal -we don't know. I don't anyway. There are many other criteria that influence trans strength too, to be honest; bearing size and design, shaft sizes, gear widths, spline lengths, case strength...probably a lot more. The ZF6 weighs ~25 lbs more than the T56 -evidence of "more beef". Hopefully, this actual data (plus the output shaft spline count provided by Jim) helps back up my original option; I would never replace a ZF6 with a T56, and that comparing the two...there is no comparison other than that they're both 6 speeds.
"The strength of a manual transmission is related to four main design functions consisting of cluster-to-mainshaft center-to-center distance, First-gear ratio, gear-tooth pitch, and the alloy of the steel used to make the gears. "
None of that is new to me... but this data from the same article was of interest to me:
Center to center;
T5 - 77mm
T56-85mm
I knew that the T56 had a substantially larger center-center distance than the T5 had....I couldn't remember the actual numbers. Anyway, 8mm. The T56 shafts are spread 8mm further than the T5 and that is where the at least a portion of it's increased tq rating came from, over the T5. However, the ZF6 goes another 10mm further than the T56! Here is what else I found:
NV3500-85mm (same as the T56)
ZF6 - 95mm
Wow. Of the 4 main design features that HRM feels govern trans stregnth, we can now confirm that the ZF6 holds a substantial advantage in 2.5 out of those 4:
*Center to center with a 10mm larger spacing
*The cut of the gears
*FIRST GEAR RATIO (about 1/2 of T56's have a numerically higher first gear ratio than the 2.68 found in the ZF6. The remainder have a similar 2.66)
The final design feature listed in HRM; the make up of the metal -we don't know. I don't anyway. There are many other criteria that influence trans strength too, to be honest; bearing size and design, shaft sizes, gear widths, spline lengths, case strength...probably a lot more. The ZF6 weighs ~25 lbs more than the T56 -evidence of "more beef". Hopefully, this actual data (plus the output shaft spline count provided by Jim) helps back up my original option; I would never replace a ZF6 with a T56, and that comparing the two...there is no comparison other than that they're both 6 speeds.
.
Last edited by Tom400CFI; May 14, 2021 at 10:35 PM.
Burning Brakes
Joined: Nov 2000
Posts: 986
Likes: 487
I hear you? But it's hard to answer when we don't know what you're actually asking for.
I'll leave this for you, from another thread, since it's pretty heavily loaded with good transmission info (EDIT: IDK why the forum broke each of those single quotes into two quotes. WTF......
and
.
I'll leave this for you, from another thread, since it's pretty heavily loaded with good transmission info (EDIT: IDK why the forum broke each of those single quotes into two quotes. WTF......
and
.
A 4+3 to ZF is about the simplest manual trans swap there is in a C4, is it not?
With a TKX swap running $4000-$5000, what do you think a ZF swap into a 4+3 car would run? Can they be found? What about ancillary parts (clutch, flywheel, pedal, bearings, etc...)?
Melting Slicks
Joined: Jun 2011
Posts: 2,383
Likes: 385
From: Leland , North Carolina
https://corvettesalvage.com/product/...ion-1989-1996/