Persistent Shifting Issue
10-22-2007, 09:23 AM
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Persistent Shifting Issue I have done a LOT of reading and testing of theories on a persistent shifting issue I have had since I bought my car over a year ago and I can not get rid of it. The car shifts fairly well 1-2, horribly 2-3 (like hitting a wall inbetween gears), not so well 3-4 (similar to 2-3), totally smooth 4-5, and not so bad 5-6. I will list below all of the things I have done that have not helped, and I have also let others drive the car with the same results to make sure it wasn't just me.
- Two different clutches (Spec 3, Spec 2) besides stock when I bought it and a new Spec billet steel flywheel
- New slave cylinder
- Two new throwout bearings
- New Pilot bearings
- New master cylinder
- Drill mod on new master cylinder
- Multiple clutch bleeds
- Stock transmission rebuilt
- And finally, because i wanted the better gearing and with hopes of solving this issue once and for all, a brand new GTO transmission
Now, I have NOT beat on the new transmission since it is still in the 500 mile break-in period (400 to go), but just driving around normally I can tell the issue has not been resolved. The interesting thing is that the specifics of the problem (which gears are difficult, how difficult each is, etc) are exactly the same as before the tranny swap.
The only thing I have left to replace that I can think of is my shifter; I currently have a Pro 5.0 that came with the car. My brother also has an 02 Z28 with a Pro 5.0 and his car is the smoothest shifting car in the world, so even though it's the same shifter, I'm gonna swap them and see if it makes a difference at all. Perhaps mine was defective from the factory or it got damaged by the previous owner or something.
Anyways, if anyone can think of any other possible causes that I could throw MORE money at, please let me know, because this shifter swap is my last desperate attempt at resolution. Thanks.
- Two different clutches (Spec 3, Spec 2) besides stock when I bought it and a new Spec billet steel flywheel
- New slave cylinder
- Two new throwout bearings
- New Pilot bearings
- New master cylinder
- Drill mod on new master cylinder
- Multiple clutch bleeds
- Stock transmission rebuilt
- And finally, because i wanted the better gearing and with hopes of solving this issue once and for all, a brand new GTO transmission
Now, I have NOT beat on the new transmission since it is still in the 500 mile break-in period (400 to go), but just driving around normally I can tell the issue has not been resolved. The interesting thing is that the specifics of the problem (which gears are difficult, how difficult each is, etc) are exactly the same as before the tranny swap.
The only thing I have left to replace that I can think of is my shifter; I currently have a Pro 5.0 that came with the car. My brother also has an 02 Z28 with a Pro 5.0 and his car is the smoothest shifting car in the world, so even though it's the same shifter, I'm gonna swap them and see if it makes a difference at all. Perhaps mine was defective from the factory or it got damaged by the previous owner or something.
Anyways, if anyone can think of any other possible causes that I could throw MORE money at, please let me know, because this shifter swap is my last desperate attempt at resolution. Thanks.
10-22-2007, 10:59 AM
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If I remember correctly, the Pro 5.0 shifters have adjustable stops...that's probably what the problem is. Also make sure that the shifter is aligned properly and that your shifter still has the little plastic bearing at the ball of the shifter. (this is the round ball that fits into the slider for the trans.
10-22-2007, 12:52 PM
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Yeah, I've adjusted the stops a few times to no avail. I will check for that plastic bearing at the ball of the shifter, but what do you mean by "aligned properly"? There are four bolts/holes and they only go in one way with no adjustment. Is there something on the shifter itself that I missed that can be "aligned"? I will take a look at that also when I pull it out and let you know how it goes. Thanks for the advice!
Any other ideas, guys?
Any other ideas, guys?
10-22-2007, 06:33 PM
#4
If the bolt holes were elongated some how this might cause the shifter to be out of alignment. Sounds crazy but I've seen it. Also make sure that the shifter is bolted down nice and tight. My vette was having problems similar to yours and it turned out that the shifter was loose. Easy fix.
Other than that I would say the problems lays in the synchros...but since you replaced the entire trans, that can't be.
Do you have an aftermarket clutch? I've seen people who don't put the 1/8" spacer behind the slave and have this kind of problem. GM clutches don't require it but aftermarket clutches do. Without the spacer, the clutch slave doesn't unspring the entire way, thus leading to insufficient clutch engagement. The only way to really see that is pop the trans and slave off. These spacers can be bought from most performance shops that sell clutches. Speed Inc sells them for $15.
Other than that I would say the problems lays in the synchros...but since you replaced the entire trans, that can't be.
Do you have an aftermarket clutch? I've seen people who don't put the 1/8" spacer behind the slave and have this kind of problem. GM clutches don't require it but aftermarket clutches do. Without the spacer, the clutch slave doesn't unspring the entire way, thus leading to insufficient clutch engagement. The only way to really see that is pop the trans and slave off. These spacers can be bought from most performance shops that sell clutches. Speed Inc sells them for $15.
10-22-2007, 07:59 PM
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Yeah, it's a Spec 2 clutch, but both the Spec 3 I had previously AND this stage 2 had/have the spacer behind the slave. I was worried it wasn't in there, so I double checked when I pulled the old trans and it was there. Now I made sure to put it on this one, as well. Both clutches were installed by ASE techs at a Chevy dealership, so I'm not worried about install error.
And yeah, it's a brand new Six Speeds Inc tranny, so I HIGHLY doubt it's the trans. Tomorrow night I plan on swapping in my brother's shifter. Like I said, it's the same shifter (Pro 5.0), but his car shifts perfectly, so if it still persists with his shifter, at least I'll know it's not that. Maybe I'll go get started on that right now since it's going to rain tomorrow...
Thanks again for the input! I'm surprised no one else has chimed in (maybe there really IS nothing else to fix, hahaha).
And yeah, it's a brand new Six Speeds Inc tranny, so I HIGHLY doubt it's the trans. Tomorrow night I plan on swapping in my brother's shifter. Like I said, it's the same shifter (Pro 5.0), but his car shifts perfectly, so if it still persists with his shifter, at least I'll know it's not that. Maybe I'll go get started on that right now since it's going to rain tomorrow...
Thanks again for the input! I'm surprised no one else has chimed in (maybe there really IS nothing else to fix, hahaha).