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1990 Corvette ZR1 Question for Owners

 
Old 01-27-2019, 02:42 AM
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grantar2
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Default 1990 Corvette ZR1 Question for Owners

Did the ZR1 use the same ZF6 speed as the base car? If so did the ZR1 have a dual mass clutch or did it have a standard flywheel. I remember reading somewhere that the gear box was the same manual on all 1990 cars, but that the ZR1 used a single mass (standard) flywheel and used a longer throw out fork?

Thanks for the input.
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Old 01-27-2019, 03:26 AM
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SI67
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This would be better posted in the C4 section.
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Old 01-29-2019, 08:39 AM
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Paul Workman
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Originally Posted by grantar2 View Post
Did the ZR1 use the same ZF6 speed as the base car? If so did the ZR1 have a dual mass clutch or did it have a standard flywheel. I remember reading somewhere that the gear box was the same manual on all 1990 cars, but that the ZR1 used a single mass (standard) flywheel and used a longer throw out fork?

Thanks for the input.
The transmission (ZF) is the same except the input (nose) shaft is bigger on the ZR-1. And, the ZR-1 utilized a dual mass FW as well.

For in-depth discussion on the differences, I would refer you to Bill Boudreau of ZFdoc.com.
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Old 01-29-2019, 11:49 AM
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ccmano
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To be precise the ZR-1 input shaft is longer than the standard car. It used a dual mass flywheel which is not interchangeable with the LT1 version due to a different bolt configuration. Not sure about the clutch fork but I do believe they are the same. Again, ZFdoc.com is the best source.
H
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Old 01-29-2019, 02:04 PM
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henryr
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dont think so....

in addition to the above

i thought the 90 cars did not use synchros on the first couple of gears and the gears were straight cut

???
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Old 01-29-2019, 03:42 PM
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Originally Posted by henryr View Post
dont think so....

in addition to the above

i thought the 90 cars did not use synchros on the first couple of gears and the gears were straight cut

???
Pretty sure all C4 ZFs were straight cut up through 92, I know they were straight cut in the 92 LT1 I had years ago.
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Old 01-29-2019, 05:31 PM
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ccmano
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All ZFS6 transmissions have full synchros in all forward gears. None have straight cut gears. The straight cut gear story comes from the change that was made in the transmission in 1993 when the torque rating was dropped from 610NM to 540NM. To quiet the transmission in low gears the gear engagement angle was increased. The gear engagement had always been angled, they simply increased it. This resulted in the lower torque rating. For some reason people assumed they went from straight cut to angled gears but that’s simply not true. In 1995 what we know as the Blue Label transmission was introduced. The previous label was Black. The blue labels are transmissions that were assembled in the US, whereas the Black labels were assembled in Germany. Blue labels also eliminated the lift ring for reverse and simply use what’s called “crash through” to get to reverse. Finally, Blue Labels use a slightly different release bearing with a smaller diameter center opening to fit the smaller diameter guide tube. The input shafts between Blue and Black labels are actually the same. The guide tubes that protect the input shafts are different. Again ZFDoc.com is the authority.
Hope that helps
H
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Old 01-29-2019, 06:19 PM
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Evan70
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Ahh, thanks for the reminder. Yes, engagement angle was increased in 93, lowering torque rating and reducing noise. I can definitely testify that the earlier transmissions are louder than the later.
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Old 02-06-2019, 10:44 AM
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Paul Workman
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Originally Posted by ccmano View Post
All ZFS6 transmissions have full synchros in all forward gears. None have straight cut gears. The straight cut gear story comes from the change that was made in the transmission in 1993 when the torque rating was dropped from 610NM to 540NM. To quiet the transmission in low gears the gear engagement angle was increased. The gear engagement had always been angled, they simply increased it. This resulted in the lower torque rating. For some reason people assumed they went from straight cut to angled gears but that’s simply not true. In 1995 what we know as the Blue Label transmission was introduced. The previous label was Black. The blue labels are transmissions that were assembled in the US, whereas the Black labels were assembled in Germany. Blue labels also eliminated the lift ring for reverse and simply use what’s called “crash through” to get to reverse. Finally, Blue Labels use a slightly different release bearing with a smaller diameter center opening to fit the smaller diameter guide tube. The input shafts between Blue and Black labels are actually the same. The guide tubes that protect the input shafts are different. Again ZFDoc.com is the authority.
Hope that helps
H
Transmission noise? WHAT noise?? I doan hear no transmission noise!!!
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Old 02-06-2019, 11:04 AM
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Originally Posted by Paul Workman View Post
Transmission noise? WHAT noise?? I doan hear no transmission noise!!!
Can't hear any transmission noise, the radio, passenger or anything else over my 1st gen B&B.
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Old 02-06-2019, 11:20 AM
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Dynomite
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Originally Posted by Paul Workman View Post
Transmission noise? WHAT noise?? I doan hear no transmission noise!!!
Me neither
I used a New Blue Label ZF S6-40 Transmission in my 91.
I had Bill (ZFdoc) rebuild a 91 Black label ZF S6-40 Transmission with Short Shifter eliminating the lift ring for reverse for my 95'
The two ZF S6-40 Transmissions (Black Label and Blue Label) take different (Inside Diameter) Throw Out Bearings.
I use the same Needle bearing Pilots in ALL Zs.
Also have a ZF S6-40 Black Label Transmission in a 90' Base Corvette with L98

I use the same 4.4 pints of TWS 10W60 Castrol in ALL ZF S6-40 Tramsmissions.


Last edited by Dynomite; 02-06-2019 at 11:56 AM.
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Old 02-12-2019, 10:43 PM
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Mr. Gizmo
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A bit off topic. Having had a c4zr1. The zf transmission even with the stock shifter felt substantial and shifted well. One of my favorite things about the car.
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Old 02-21-2019, 09:42 AM
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Originally Posted by Dynomite View Post
Me neither
I used a New Blue Label ZF S6-40 Transmission in my 91.
I had Bill (ZFdoc) rebuild a 91 Black label ZF S6-40 Transmission with Short Shifter eliminating the lift ring for reverse for my 95'
The two ZF S6-40 Transmissions (Black Label and Blue Label) take different (Inside Diameter) Throw Out Bearings.
I use the same Needle bearing Pilots in ALL Zs.
Also have a ZF S6-40 Black Label Transmission in a 90' Base Corvette with L98

I use the same 4.4 pints of TWS 10W60 Castrol in ALL ZF S6-40 Tramsmissions.

Hey Cliff, you must have a stash of the oil somewhere. I used to get it at my BMW dealer, but unfortunately they no longer carries the TWS.

Speaking to Marc Haibeck, I asked him for his recommendation - what he now uses in the transmissions. He put me onto REDLINE HEAVY SHOCKPROOF (100% synthetic) GEAR OIL. I use it now in both the trans AND the differential (GM friction modifier added to the differential). I can't really tell much if any difference in the shift feel; both the TWS and the RL synthetic seems to be GOOD stuff. (I change my trans oil every other season or 10k miles, whichever occurs first.)
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Old 02-21-2019, 10:02 AM
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Evan70
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Originally Posted by Mr. Gizmo View Post
A bit off topic. Having had a c4zr1. The zf transmission even with the stock shifter felt substantial and shifted well. One of my favorite things about the car.

I had Pete put in one of Bill's short shifters when we did the 391, and while it's a good shifter and probably better for fast shifting, I actually think the stock shifter was better for casual driving.
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