ZF 6SPD 0r T 56
10-21-2018, 08:54 PM
#4
Team Owner
Pro Mechanic
Difference between what? A ZF6 and a T56? There is a big difference;
1. The ZF^ shifts way, WAY better
2. The ZF6 has prvisions for the C4's C-beam mount already on it
3. The ZF6 is bomb proof and the T56 is not.
4. The T56 is easier to source and to source parts for. Unfortunately, at some point, you'll NEED parts for the T56.
There are a plethora of other differences, but those are the big/meaningful ones.
Hold on. T56 "came out" in '97 in the Corvette....which is pretty irrelevant b/c it came out as a rear mounted transaxle...meaning any '97^ 'Vette T56 won't work at all in a C4.
The T56 actually came out in 1992 in the Viper, then in '93 in the F-bodies. '93 - '97 F-body T56's would be the easiest to put into a C4, of all the T56's.
1. The ZF^ shifts way, WAY better
2. The ZF6 has prvisions for the C4's C-beam mount already on it
3. The ZF6 is bomb proof and the T56 is not.
4. The T56 is easier to source and to source parts for. Unfortunately, at some point, you'll NEED parts for the T56.
There are a plethora of other differences, but those are the big/meaningful ones.
The T56 actually came out in 1992 in the Viper, then in '93 in the F-bodies. '93 - '97 F-body T56's would be the easiest to put into a C4, of all the T56's.
10-22-2018, 09:34 AM
#7
Race Director
zf6 is basically a notchy, noisy, long throwed, heavy weight, truck transmission adapted for use in the c4 corvette.
its only redeeming quality is it is heavy duty and can take a lot of power.
Ive also never (knock on wood) went for 3rd and got 1st - at least with the hurst short throw shifter i have on it. Though i did have that happen once with stock shifter. No damage thank goodness. I also saw a c4 ‘spin out’ during a parade lap and thats what caused it (guy went for 3rd and got 1st - oops).
If you dont like the long throws you can put on a shorter throw shifter but it will become more notchier/more shift effort (ie doesnt shift like a honda)
38 lb Factory dual mass flywheel is part of the reason why its so heavy and can be swapped out to aluminum 12 lb unit. Some people dont like doing this bc the dual mass dampens the noise - but you can put a thicker shim on the countershaft to reduce rattle and get the best of both worlds.
Simply put in a stage 3+ clutch or dual disk mcleod and its ready for tons of power out of the box.
its only redeeming quality is it is heavy duty and can take a lot of power.
Ive also never (knock on wood) went for 3rd and got 1st - at least with the hurst short throw shifter i have on it. Though i did have that happen once with stock shifter. No damage thank goodness. I also saw a c4 ‘spin out’ during a parade lap and thats what caused it (guy went for 3rd and got 1st - oops).
If you dont like the long throws you can put on a shorter throw shifter but it will become more notchier/more shift effort (ie doesnt shift like a honda)
38 lb Factory dual mass flywheel is part of the reason why its so heavy and can be swapped out to aluminum 12 lb unit. Some people dont like doing this bc the dual mass dampens the noise - but you can put a thicker shim on the countershaft to reduce rattle and get the best of both worlds.
Simply put in a stage 3+ clutch or dual disk mcleod and its ready for tons of power out of the box.
10-22-2018, 11:35 AM
#8
Team Owner
Pro Mechanic
That's funny...you just totally described...to a "T", the T56 that is in my wife's CTS-V! Notchy (add "shift thwarting synchros), noisy (lots of bearing noise transmitted up through the shifter, even in 4th, 5th and 6th, where the ZF is quiet), long throwed (you could hit the center stack with your knuckles in 1st, 3rd, 5th and reverse on hard shifts), heavy, and adapted.
The diff is that it's only redeeming quality is definitely NOT that it's heavy duty, b/c it's not.
You could do that with any trans, in any car. That's called "bad driving". Well....maybe you couldn't do that in a T56 equipped car b/c the synchros aren't good enough to let you into 1st gear when you're at the top of 2nd. 
The diff is that it's only redeeming quality is definitely NOT that it's heavy duty, b/c it's not.
10-22-2018, 12:37 PM
#9
Race Director
That's funny...you just totally described...to a "T", the T56 that is in my wife's CTS-V! Notchy (add "shift thwarting synchros), noisy (lots of bearing noise transmitted up through the shifter, even in 4th, 5th and 6th, where the ZF is quiet), long throwed (you could hit the center stack with your knuckles in 1st, 3rd, 5th and reverse on hard shifts), heavy, and adapted.
The diff is that it's only redeeming quality is definitely NOT that it's heavy duty, b/c it's not.
You could do that with any trans, in any car. That's called "bad driving". Well....maybe you couldn't do that in a T56 equipped car b/c the synchros aren't good enough to let you into 1st gear when you're at the top of 2nd.
The diff is that it's only redeeming quality is definitely NOT that it's heavy duty, b/c it's not.
You could do that with any trans, in any car. That's called "bad driving". Well....maybe you couldn't do that in a T56 equipped car b/c the synchros aren't good enough to let you into 1st gear when you're at the top of 2nd.
Tom, i saw some stupid stuff in this corvette racing club.
With one old guy, it was common for the road course corner workers to see his wheel coming around the corner before his car (ie. 2 yrs in a row he forgot to torque his race wheels and had wheel-off incidents on the course). The second year he got confused at the finish and ran over all the timing lights/equipment preventing lap times for the remainder of the event.
his c4 had a c5 bodykit on it if that tells you anything 😂
10-22-2018, 12:39 PM
#10
Team Owner
Pro Mechanic
Yikes. Fodder for good stories...at least! 
10-22-2018, 01:41 PM
#11
Race Director
The zf6 was also used in a good number of German cars, the m5 for one. It's a good transmission.