C4 Tech/Performance L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

Will this cause rough/notchy zf6 gear changes?

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Old Jan 18, 2024 | 12:57 PM
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Default Will this cause rough/notchy zf6 gear changes?

Bubbles show up in my clutch master reservoir when I pump the pedal. They are very small bubbles, very small. I just got the trans rebuilt and blue printed by Bill B, zf doc/zr51 performance. I'm tired of these horrid gear changes. Makes me feel like I'm driving a pos. I have bled it a million times.
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Old Jan 18, 2024 | 01:00 PM
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Are you using correct manual 5w-30 SYNCROMESH trans oil?

or are you using Castrol BMW motor oil in your transmission?
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Old Jan 18, 2024 | 01:49 PM
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Amsoil 5w30 synchromesh
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Old Jan 18, 2024 | 02:28 PM
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Originally Posted by 1993C4LT1
Amsoil 5w30 synchromesh
then i would guess the problem has got to be in your hydraulics

clutch master / line or slave

When ive had problems, its always been in the slave

2x ive had the experience of the clutch pedal not working bc there was a slow leak in the slave

never had an issue of my OE slave (stupidly tossed it after proactively replacing it)

1 issue on a TRW slave 16000 miles on it
1 issue on a Jim Jandik rebuilt slave 20000 miles on it

the only time i had notchy shifts was when i put bmw castrol 10w-60 ipo of the factory fluid

was especially bad if trying to shift at high rpm like in a dragstrip situation. Lever wouldnt even move into the next gear

Last edited by dizwiz24; Jan 19, 2024 at 09:10 PM.
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Old Jan 19, 2024 | 08:41 PM
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u will need this:

https://www.corvetteforum.com/forums...post1607302274
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Old Jan 19, 2024 | 09:09 PM
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OP no longer has the factory clutch as he has converted to the push style RAM setup.


I would be taking a look at the connections for the lines. But I would expect you to be noticing a fluid drop in the reservoir. This could also be a red herring on your grinding issues. I would be worried on the spacing of the slave that was done.
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Old Jan 19, 2024 | 11:50 PM
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Trans doesn't grind. I have looked at the lines. No leaks. I never notice the fluid level in the reservoir drop.

Correct, car now has ram clutch.

Clutch pedal has play, but only at the first inch of travel. All I have to do is pump where there is "free play", bubbles show up in the reservoir.

As far as the spacing for the slave, I ended up re measurring the 2nd time my dad and I removed the trans. We ended up having to use all 3 spacers. As did another (pedcricd) forum member who went with the same clutch and flywheel as me.

I have a brandnew stock clutch line and clutch master if I need them.

Also have a new Tilton clutch master and clutch line if I need them.
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Old Jan 19, 2024 | 11:55 PM
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Originally Posted by VikingTrad3r
I even did that procedure when I was on stock hydraulics. Same as the car is now.
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Old Feb 10, 2024 | 07:28 AM
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Quick update. After doing some tests/checks zf doc told me to do, he concluded that the trans has to go back to him. He offered me to ship the whole car. So, my car got shipped yesterday.
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Old Feb 14, 2024 | 12:11 PM
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Originally Posted by 1993C4LT1
Quick update. After doing some tests/checks zf doc told me to do, he concluded that the trans has to go back to him. He offered me to ship the whole car. So, my car got shipped yesterday.
That sounds expensive.
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Old Feb 14, 2024 | 06:48 PM
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Yup but hell, what am I supposed to do? He says he won't charge anything other than labor to r&r the trans.
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Old Feb 14, 2024 | 11:03 PM
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Sounds more expensive than just shipping the transmission, but you're probably ready to drive it rather than continuing to wrench on it.
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Old Feb 15, 2024 | 07:50 AM
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I shipped the whole car, because I didn't want anything to be on "me", transmission wise. Shipping the trans wasn't cheap either. But yes, the whole car, a lot more. I just want my car right. Especially with spring and summer near.
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Old Feb 15, 2024 | 11:10 PM
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My car has vibrations at 3k rpm and above.

Never had this prior to the trans removal.

Even has the vibration when you rev it, at idle.

Bill B(ZF Doc) believes it is the flywheel balance. But, RAM flywheels do not require balancing. So, he is going to talk to Mike, owner of RAM clutches, tomorrow.

Either way, this is an interesting situation to be in. See my screenshots.



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Old Feb 15, 2024 | 11:38 PM
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so did bill have to become a walmart greater or did ur dmf have weights on engine side?


Originally Posted by 1993C4LT1
My car has vibrations at 3k rpm and above.

Never had this prior to the trans removal.

Even has the vibration when you rev it, at idle.

Bill B(ZF Doc) believes it is the flywheel balance. But, RAM flywheels do not require balancing. So, he is going to talk to Mike, owner of RAM clutches, tomorrow.

Either way, this is an interesting situation to be in. See my screenshots.


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Old Feb 16, 2024 | 06:57 AM
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Originally Posted by 1993C4LT1
Quick update. After doing some tests/checks zf doc told me to do, he concluded that the trans has to go back to him. He offered me to ship the whole car. So, my car got shipped yesterday.
So Bill rebuilt your transmission before the RAM install?
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Old Feb 16, 2024 | 07:02 AM
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I will look at my oem flywheel shortly, and post pics of it. He also says the vibration is due to an ignition problem. I have never touched the plugs or wires since I have owned this car. I can for certain, car doesn't misfire and pulls effing awesome-smooth with no pauses to redline.
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Old Feb 16, 2024 | 07:02 AM
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Originally Posted by grandspt
So Bill rebuilt your transmission before the RAM install?
Yes sir, that is correct.
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Old Feb 16, 2024 | 07:18 AM
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Brandon, please continue to keep this thread updated I am interested to see how this progresses and if your issue is resolved.
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Old Feb 16, 2024 | 07:50 AM
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Absolutely. I really hope it does.
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