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

ZF Transmission issues

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Old 10-18-2016, 07:41 PM
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Need A Vette
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Default ZF Transmission issues

Well I just bought an '89 on Sunday, and haven't had any issues, until now. Recharged the A/C tonight and took it for a short drive of 2-3 miles, and now I have 3-4-5-6, but no 1-2. I dont get it, no strange noises, no unusual or excessive effort in the shifter. Clutch still feels the same.

I dont have an FSM or anything to guide me in the right direction. Just kinda frustrated right now...

Thanks,

D.

Last edited by Need A Vette; 10-18-2016 at 07:41 PM.
Old 10-18-2016, 08:59 PM
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I would check the linkage first, has the 1-4 skip shift been disabled?
Old 10-19-2016, 12:42 AM
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96GS#007
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Originally Posted by We Gone
I would check the linkage first, has the 1-4 skip shift been disabled?
There's no external linkage to check on the ZF6.

1-4 lock out would prevent 2-3 not 1-2

OP...
Check the clutch fluid. When it gets low, the shifting can become a bit quirky with the ZF6, ultimately failing completely.

If the fluid is ok, you'll need to look at the transmission and ensure that the shifter "box" is still attached to the rear of the transmission. It actually is designed to move, and the bushings can go bad.

Next verify the slave cylinder is firmly bolted to the bell housing. There are two nuts....either 10 or 13mm, I don't recall of the top of my head...that secure the slave on a couple studs.

Failing all the above, drain the lube and look for chunks.

Can you shift into first or second with the car stopped and the engine off? If no, unfortunately that is usually a sign of something internal to the ZF6. If yes, it tends to be one of the aforementioned items.

pic to help visualize the shifter box...

Old 10-19-2016, 06:18 AM
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The answer is NO, I can't even move the shifter to the 1-2 part of the shifter gate. I'm thinking the 1-2 shifter rod is out of alignment. Cam the shifter be pulled with the trans in the car, and the rod aligned? I wasn't driving it hard, made a left turn, downshifted to 3rd, and got home, still no 1-2. Frustrating, how a trans so durable tears up on the 3rd outing in the car.

D.
Old 10-19-2016, 07:25 AM
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Originally Posted by Need A Vette
The answer is NO, I can't even move the shifter to the 1-2 part of the shifter gate. I'm thinking the 1-2 shifter rod is out of alignment. Cam the shifter be pulled with the trans in the car, and the rod aligned? I wasn't driving it hard, made a left turn, downshifted to 3rd, and got home, still no 1-2. Frustrating, how a trans so durable tears up on the 3rd outing in the car.

D.
Shift select for the ZF is essentially "all internal" - a shifter group problem? Seems unlikely but .....

There's two shift sections in this ZF parts manual 1 - 2 is in the 2nd image 621 the rail, 622 the fork and 615 the shift select shaft. There are better images out there but this is a very good "quick glimpse" of the ZF.

Shifter group is in a separate image.

http://www.zfdoc.com/S640Parts.htm
Old 10-19-2016, 09:53 AM
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Originally Posted by 96GS#007
There's no external linkage to check on the ZF6.

1-4 lock out would prevent 2-3 not 1-2


OK..... sorry I posted but I have seen a case were this pin came particularly out of the (linkage) and created a bind. I have also seen the skip shift solenoid stick and cause issues.


Last edited by FASTAZU; 10-19-2016 at 09:56 AM.
Old 10-19-2016, 10:02 AM
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Originally Posted by We Gone
OK..... sorry I posted but I have seen a case were this pin came particularly out of the (linkage) and created a bind. I have also seen the skip shift solenoid stick and cause issues.
I believe that you meant "partially" and I can understand maybe that creating an issue. It's not a very "particularly" easy operation to view but it certainly can be done "in the car" - worth a look for sure!!

OP - do you know if your car has had an after-market shifter installed? An '89 if it didn't have the lift-ring for reverse might hint an after-market shifter. Maybe you check the ZF tag on the case and confirm the assembly number.
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Old 10-19-2016, 10:10 AM
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Stock shifter, as it still has the lift ring reverse lock out. Just a bit frustrated, as I wasn't flogging the car or power shifting.

D.
Old 10-19-2016, 08:42 PM
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Default Kudos to Bill Boudreau!!!

I have remotely encountered this type of problem twice during technical assistance events in the past. The problem is likely in the shifter assembly and can be resolved without removing the transmission. Removal of the exhaust and shifter assembly will be required to service the shifter assembly on the bench. To better understand what part needs to be fixed in the shifter, go to the following link http://zfdoc.com/S640Parts.htm and page down to the 700 position group for exploded view of parts in the shifter assembly. There are two pages with the same diagram. Look for position 709 axle and two clamping fixtures 704. What likely has happened is the driver’s side clamping fixture 704 is no longer installed (may be sitting down in the rubber bellows) allowing the axle 709 to work its way out of the left axle hole in the cardon joint 708. This requires compressing the axle laterally with one of the two clamping fixture already installed then installing the second retaining fixture. If you want to send the shifter assembly to me to reinstall the clamping fixture, I could turn it around in one day. Maybe this would be a good time to install a short throw lift-ring gear shift lever ($250) plus $50 labor and shipping. The attached procedure will help guide you through the shifter removal process if needed. Let me know if you have any questions.

Best regards,

Bill Boudreau
ZR51 Performance


Now that is what makes this forum so F'n AWESOME!!!

Last edited by Need A Vette; 10-19-2016 at 08:43 PM.
Old 10-19-2016, 08:55 PM
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Nice..
Old 10-20-2016, 08:54 PM
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Default Console Removal

Well got home from work tonight and started tearing into it, was able to get the 'top' portion of the console off, but still need to remove the part that is attached to the trans tunnel. I've removed every screw, bolt, etc that I can find, yet the console is still firmly in place, and I need to remove it to remove the rubber boot in order to gain access to the shifter in order to remove it, and press the pin back in. What am I missing!?? BTW this is on an '89

Any guidance would be greatful and appreciated.

Thanks

D.

Last edited by Need A Vette; 10-21-2016 at 07:00 AM.
Old 10-23-2016, 07:51 PM
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I know some of you have followed and looked at this thread, alas Today I finally was able to get back to it. All I can say is IF your 6 sp vette ever slips a transverse shifter rod, HAVE SOMEONE ELSE FIX IT!!! Took me Literally ALL DAY LONG to get this fixed! working in VERY TIGHT quarters. Another word of advice, Put the Drivers side 'E' clip on FIRST, then push the rod back through and put the one on the Passenger side. There is more room on the right side, but still a bitch. besides that I think there are now several, 4-6 E clips sitting in the bottom of the rubber bellows. I went a step further and to prevent this from happening again, put a small dab of JB Weld on the Clips to prevent their coming off again. Still need to put everything back together, shift boots, Lower, and Upper console, and should be ready to go. While I was at it, I cleaned the entire shifter linkage with Brake Cleaner, and then sprayed everything down with lube, shifts like it never has before, smooth, and barely any effort.

Oh well just another day with an almost 30 year old car, it was a great day though, mid 60s, and completely cloudless, a great day to be outside.
Old 10-24-2016, 09:44 AM
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Great job, now you can enjoy 1-2 gear again.
Old 10-24-2016, 04:10 PM
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Persistence pays off! Despite the frustrations, it was another successful C4 repair... I love it!
Old 10-27-2016, 08:56 AM
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Good job!

It is always a good feeling to get a job done and working good. To me it is half the fun of having hobby/specialty cars that can be repaired/modded.


Originally Posted by Need A Vette
... was able to get the 'top' portion of the console off, but still need to remove the part that is attached to the trans tunnel. I've removed every screw, bolt, etc that I can find, yet the console is still firmly in place...... What am I missing!??......
Did you find how to remove the side? If so, what were you (and me) missing?

I had a similar issue when I did a clutch/transmission swap. I never did get the side off. Instead I worked in a very tight space to get the shift boot back on the tunnel. I could get it without removing the side of the console, but it was a pain.
Old 10-27-2016, 03:35 PM
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Now, did everything from the top, as difficult as it was, my big *** fingers trying to manipulate the 'E' rings into place and snapping them down.

But got it done.

D.

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