Any good shops for C4 work?
Thread Starter
Race Director
Joined: Oct 2011
Posts: 16,096
Likes: 820
From: Dallas Texas
2025 C4 of the Year Finalist - Modified
Any good shops for C4 work?
I have a 96 lt4 that I believe needs transmission work. Imo, it shifts way too notchy. Stock shifter. And I'd like to see if the rod bearings, and bottom end is OK etc because I want mild cam. Just an lt4 hotcam or something.
I can do stuff like optisparks all day. But not super involved stuff like mentioned above.
Doesn't really matter to me where the shop is located, in the nation. If nothing, then I guess I better learn to do the more involved work. But of course, time is the enemy.
I can do stuff like optisparks all day. But not super involved stuff like mentioned above.
Doesn't really matter to me where the shop is located, in the nation. If nothing, then I guess I better learn to do the more involved work. But of course, time is the enemy.
Drifting
Joined: Jan 2021
Posts: 1,315
Likes: 385
From: Northern California
ZF6 gearbox work is a pretty specialized field, and to my knowledge there are only two places that can do good work there. Rockland Standard Gear in NY and ZFDoc in Arizona. It's expensive but the results speak for themselves if you want to keep the car and have it drive well. Before you go too far in any transmission work, make sure that your clutch hydraulics (master/slave cylinders) are operating perfectly, no leaks, no air in system, full slave travel, etc. Then you can assess the state of your actual gearbox better.
Some had experiences which showed a change of lubricant over to the Castrol synthetic / BMW oil or the AMSOIL Manual Transmission Fluid synchromesh 5W/30 has improved their shift quality, but like I said above the clutch hydraulics and the state of the pressure plate / disc / flywheel are critical to good shifting quality so look there first.
The forum is full of posts pertaining to both of the above topics so search to your heart's content and YMMV. Ton of good info here.
Engine bearings, rods, bottom end, etc. are all probably available locally with a high degree of skill in the Dallas area. Several forum members here and in the C4 ZR1 forum can chime in with their thoughts and recommendations.
Good luck.
Some had experiences which showed a change of lubricant over to the Castrol synthetic / BMW oil or the AMSOIL Manual Transmission Fluid synchromesh 5W/30 has improved their shift quality, but like I said above the clutch hydraulics and the state of the pressure plate / disc / flywheel are critical to good shifting quality so look there first.
The forum is full of posts pertaining to both of the above topics so search to your heart's content and YMMV. Ton of good info here.
Engine bearings, rods, bottom end, etc. are all probably available locally with a high degree of skill in the Dallas area. Several forum members here and in the C4 ZR1 forum can chime in with their thoughts and recommendations.
Good luck.
Thread Starter
Race Director
Joined: Oct 2011
Posts: 16,096
Likes: 820
From: Dallas Texas
2025 C4 of the Year Finalist - Modified
ZF6 gearbox work is a pretty specialized field, and to my knowledge there are only two places that can do good work there. Rockland Standard Gear in NY and ZFDoc in Arizona. It's expensive but the results speak for themselves if you want to keep the car and have it drive well. Before you go too far in any transmission work, make sure that your clutch hydraulics (master/slave cylinders) are operating perfectly, no leaks, no air in system, full slave travel, etc. Then you can assess the state of your actual gearbox better.
Some had experiences which showed a change of lubricant over to the Castrol synthetic / BMW oil or the AMSOIL Manual Transmission Fluid synchromesh 5W/30 has improved their shift quality, but like I said above the clutch hydraulics and the state of the pressure plate / disc / flywheel are critical to good shifting quality so look there first.
The forum is full of posts pertaining to both of the above topics so search to your heart's content and YMMV. Ton of good info here.
Engine bearings, rods, bottom end, etc. are all probably available locally with a high degree of skill in the Dallas area. Several forum members here and in the C4 ZR1 forum can chime in with their thoughts and recommendations.
Good luck.
Some had experiences which showed a change of lubricant over to the Castrol synthetic / BMW oil or the AMSOIL Manual Transmission Fluid synchromesh 5W/30 has improved their shift quality, but like I said above the clutch hydraulics and the state of the pressure plate / disc / flywheel are critical to good shifting quality so look there first.
The forum is full of posts pertaining to both of the above topics so search to your heart's content and YMMV. Ton of good info here.
Engine bearings, rods, bottom end, etc. are all probably available locally with a high degree of skill in the Dallas area. Several forum members here and in the C4 ZR1 forum can chime in with their thoughts and recommendations.
Good luck.
Thread Starter
Race Director
Joined: Oct 2011
Posts: 16,096
Likes: 820
From: Dallas Texas
2025 C4 of the Year Finalist - Modified
Everyone says a properly working zf6 should "shift like a knife through butter" mine definitely doesn't. It sometimes doesn't go into reverse all the way. If you let go of the clutch pedal slow, it will slide into the reverse gate fully. Doesnt happen all the time. Stock shifter, car is completely stock-for now.
Drifting
Joined: Feb 2017
Posts: 1,274
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From: Tacoma WA
2024 C4 of the Year Finalist - Unmodified
Just to clarify “notchy”. Do you mean you can feel it picking up the gear like the syncros are not doing their job, or more like the shifter doesn’t feel quite right? Also the fact that the clutch release pressure or time appears to make a difference would seem to indicate a clutch issue more than a shifter or transmission issue.
Safety Car
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Pro
Joined: Sep 2010
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From: Hutto Texas
From what I have read the master and slave takes a bit of effort to bleed to ensure you have 100% of the air out. How did you go about bleeding it and confirming there is no air? If any air exists it will make shifting harder which is what it sounds like you are experiencing.
If you think its a wear issue then a transmission shop that is familiar with the ZF6 is probably your best option. I am in the Austin area and my stock '95 with its original ZF6 with 187K miles still shifts very easily, no noise, no fuss, even going in to reverse.
If you think its a wear issue then a transmission shop that is familiar with the ZF6 is probably your best option. I am in the Austin area and my stock '95 with its original ZF6 with 187K miles still shifts very easily, no noise, no fuss, even going in to reverse.
Thread Starter
Race Director
Joined: Oct 2011
Posts: 16,096
Likes: 820
From: Dallas Texas
2025 C4 of the Year Finalist - Modified
I've bled it every way possible, seriously. I've done it so many times, I'm annoyed of doing it. So, I'm going to swallow my pride and take it to a shop. I did call Henderson yesterday. No answer, left a voice mail. Hopefully they call me back!
Le Mans Master
Joined: Dec 2005
Posts: 8,584
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From: Communist Colorado
I cant remember where, but I thought there was a write up on aligning the ZF shifter assembly.
EDIT** Soryy man, that was for the C5 shifter assembly... I knew I had done the process before... just couldnt remember which car... Ive had 9 Vettes over many years,,,, memory got fuzzy... Apologies.
EDIT** Soryy man, that was for the C5 shifter assembly... I knew I had done the process before... just couldnt remember which car... Ive had 9 Vettes over many years,,,, memory got fuzzy... Apologies.
Last edited by 81c3; Dec 27, 2021 at 08:29 AM.