I am having some issues and I think it may be my shifter alignment, at least I really hope it is. I have an 03 Z with a C6Z shifter from Gene Culley that I installed myself(I may not have done it right).

I went to the drag strip for the first time this past weekend and now the car will not go into 1st or 3rd. I have a stock clutch and stock driveline with 35k miles. The car is cammed and some other things and 432/417 rwhp.

After the last pass(I made 4 passes) in the 1/8th, when I went to 1st and let out the clutch the gear would grind, and if felt like the shifter was wanting to jump to the right in my hand. It was not difficult to go into 1st or 3rd with the clutch engaged, but when I would release the clutch it would grind and make it feel like the shifter would jump to the right.

Since I installed the shifter at times it would be difficult to actually get it into 1st or reverse from a dead stop. I would have to go to neutral sometimes 3-4 times to get it into reverse. Also when I would start the car and pull out of the garage(cold start after the car would sit for weeks at a time sometimes), I would place it into reverse then when I released the clutch it would sometimes(maybe 3 times) "jump" into reverse, almost like it wasn't completely in reverse, but then would "settle" in when I began to release the clutch.

I would drive the car and stop at a red light and would at times have to go into neutral several times before it would "lock" into 1st, or would go to 2nd prior then it would easily go into 1st.

I'm at a loss and am hoping for the best. This was the first time that I have raced the car since I have owned it for over 2 years, othen than some spirited driving. Any input/advice would be VERY helpful. Thanks in advance guys/gals.

 

Did you follow the shift adjustment that has multiple threads on the forum.

Heres a photo of rpms instructions which I believe are taken from the manual.




If you followed this or didnt and then do, and still have problems it could be your clutch, the LS6 clutch was only ment to hold 380-400ftlbs of torque. Or it could be the P.O.S clutch master cylinder. Or be both.

 

Your shifter rod that goes out of the lower box... has probably rotated on the shaft that goes to the trans... pretty common for those that have messed with that pinch clamp... RE align it and make sure that bolt is tight.. but don't break it or strip it out that happens too... I used blue loctite on mine

ALSO make sure the bushings in the box aren't cracked, or badly worn... IF the box is loose it won't shift right....


Use an allen wrench or drill bit if your alignment pin is missing…

One step further! I copied this;

This made a big improvement, but I occasionally would still get hung up getting into first. I took apart the console again and noticed that even with the alignment pin "in'and all 3 torx bolts loose the shifter "box" still had about 2 millimeters play forward and back. In other words you can tighten the shifter box after you push the shifter box to the front part of this play or to the back part of this play. I decided to try pushing the shifter box all the way forward, tighten everything and drive the car. This made my first gear selection problem COMPLETELY disappear BUT now second felt a bit "crunchy" going in and 3rd and 4th gear were not as easy as before. So I tried moving the shifter box to the back of the possible play and drive the car. My first gear problem came back worse than ever, but the rest of the gears were relatively smoother but not perfect.

I was back to square one... So I took a break, and when I came back i decided to totally remove the shifter box and analyze this problem. Once I removed the shifter I noticed that there is a half moon shaped cut out on the shift shaft that the 3rd torx bolt goes through. This cut out prevents the shift shaft from completely coming out of the clamp if the bolt got loose, and is obviously, exactly where the bolt is designed to go through the clamp.

What I did was I installed the shifter box back with only the 2 torx that hold it to the tunnel finger tight and left out the 3rd torx completely. I took a flash light and shined it down the hole, where the bolt goes in the clamp. It turns out that the cut out on the shift shaft can be a millimeter forward of the clamp or a millimeter aft of the clamp and the bolt will still go into the clamp fine and you can tighten it in any of these positions. Thus the 2 millimeters of play.

I made an educated guess that the cut out on the shaft should be EXACTLY aligned with the hole in the clamp (not a bit forward or back even though the bolt will still fit)so I aligned the cut out on the shaft so perfectly that when you shined a light down the hole the cut out on the shaft was not even noticeable. You could just see a perfectly round hole. I then tightened the 2 torx on the torque tube to spec and checked to see if anything moved. Nothing moved and the shaft cut out was still perfectly aligned with the hole in the clamp that holds the 3rd torx. I carefully placed the 3rd torx in the clamp and since the it was so well lined up it I could tighten it with my fingers (up to a point of course) then I carefully tightened it to spec (22 ft pounds) trying not to place any down pressure on the bolt, just rotational pressure enough to get to spec. Buttoned it all back up and WOW. All gears went in perfectly. First smooth as silk, second smooth with no crunch, third and fourth with one finger, fifth and sixth smooth.

 

...Atta boy, persistence and patience pays off again !!!...

 

Oh, pardon me...

 

Thanks for the input. I will check out the shifter first and check that. I installed the entire lower shifter assembly with the box and everything if that makes a difference. Also I did notice that after my first run at the track my clutch pedal felt different, and I am planning on an adjustable master cylinder and hope that will solve the issue or to re-align the shifter. Will keep yall updated.

 

I would also look at the clutch hydraulics as a part of the problem. Replacing the master cylinder is a good idea. I bet your fluid in the master cylinder is black and nasty~!

When it gets like that, you start building up nasty slime inside the master cylinder and it becomes inefficient and looses volume and cant make proper clutch releases.

If your going to replace the master, I strongly recommending going the extra mile and doing a complete clutch hydraulic flush and bleed!

Im another fan of making sure that the rubber isolators for the box are in good shape. If there worn and soft, they will allow the shifter to FLEX and not shift properly.

Bill

 

I know the fluid is pretty dark in the clutch fluid reservoir for sure. I remember the rear bolt that connects to the back of the shifter(where the arm from the linkage connects) it had some play in it when I installed it and that could be some of the problem also. I am going to attempt to start checking some things out today. And hopefully its a simple fix.

 

The alignment is just fine and that was not the issue. I have concluded that the trans needs to be pulled and rebuilt. I will be having this done in the next few months along with a new clutch and adjustable master cylinder. Thanks for all the help/input guys.