Notchy shifting....what's causing it???
Thread Starter
Melting Slicks
Joined: May 2000
Posts: 2,974
Likes: 5
From: CenTex Texas
Notchy shifting....what's causing it???
Four years ago I had a new tranny installed and it felt great for the next three years, but for the past year i've been increasingly getting more and more notchy type shifting. I thought it might be the throw-out bearing or even my worn original '97 stock clutch. But I just had LG install a new Z06 clutch, a new Z06 slave/throwout-bearing, and pilot bearing and the notchy shifting is still there. So it must be something else.....but i don't know what. Anyone have any suggestions?
BTW The car isn't a daily driver (only gets about 3K miles a year). I haven't been to the drags and have only participated in three AutoX's since the new tranny was installed....so i can't see wear or abuse being an issue.
Thanks!
BTW The car isn't a daily driver (only gets about 3K miles a year). I haven't been to the drags and have only participated in three AutoX's since the new tranny was installed....so i can't see wear or abuse being an issue.
Thanks!
Drifting
Joined: Mar 2005
Posts: 1,541
Likes: 76
From: Houston TX
Here is some good info that may help you. I did this on my car and man what a difference. 
http://forums.corvetteforum.com/show...ing&forum_id=1
http://forums.corvetteforum.com/show...ing&forum_id=1
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
97C5ENVY
I took a look at the linked post and added some info that may help you resolve your notchey shift issue. Here is what I addes to the referenced post:
I found this post by accident and WOW,,,I am glad that I did! Thank you guys for all of the really great info!
I want to add a few thoughts that may help clear up a few things.
First thought. There are some people who are truely having a problem with "NOTCHY" shifting issue that may be different than what we are discussing with the feel of the shifter. I believe that they are NOT talking about the detent feel but the feel that you get from the synchros not allowing the driven and engageing gear to syncronize.
The fluid in my 98 MN6 wore out and I would get that "GRINDING" feel when shifting aggresively. It was like it would skip a few teeth on the synchro and then pop into gear. I caught it early and figured out was wrong. Just changing the fluid and adding Mobil 1 Synthetic ATF made a world of difference and resolved that issue.
Second thought. For those who venture into the world of the "Afrermarket Shifter" there are a couple of things to note:
-1. Some shifters have a large bolt or screw on the front and back of the shifter body. This bolt or screw is a stop. It adjust the throw of the shift lever. The T56 really doesn't need the stop bolt because the tranny has internal stops. If someone installed your shifter for you or if you installed it and the bolt was improperly adjusted (screwed too far in) the shift lever will not be able to move the shift fork far enough and this can cause the tranny to jump out of gear. If your tranny pops out of gear and your shifter has stops, back them out and see if that helps.
The forward bolt/screw effects 1st, 3rd, and 5th. The rear bolt/screw effects 2nd, 4th and 6th. You can just see the bolts on the aftermarket shifter on the right:
-2. When you remove your old OEM shifter, this is what you will see:
The rod with the loop in the center of it, is the shift rod. It moves forward and back and also moves in an arc (side to side) Sometimes this housing and the rod get dry or dirty and the rod can hang up. That can give you a stiff notchey shift feeling also. Lubricate the rod with lithium grease if it is dry and stiff. There is also a black plastic shoe on the end of the shift rod that fits in the loop in the shift rod. If that cap breaks or wears out, it can also cause the tranny to jump out of gear because the shifter can not fully engage the shift fork into gear.
As for the OEM shifter, it does NOT have any sort of centering springs in the shifter body. If you remove the OEM shifter from the shifter housing, the shift rod will flop around like a rag doll. The centering springs are internal to the transmission. Early C5's had very weak return springs that moved the lever from the 5-6 position back to the 3 N 4 position. Later C5 trannys had a slightly stronger spring to assist centering but it still sucks. Some aftermarket shifters have adjustable return springs that make centering very positive. My Kirban is one.
As for the Antivenom shift mod, the detent is most likely there to provide a positive feel to let the driver "KNOW" that he/she is in the gear selected. As for reducing the pressure of the detent ball with a washer or going all the way and installing a plug without a detent, I guess it all has to do with personal feel. Each gear has a set of dogs that set the slider gear in place when you engage that gear. My guess is that the detent ball just helps keep the shifter handle in the gear selection gate and gives you that "yea. it's in gear" feeling. I am not a T56 tranny expert either!
I hope all of this makes sense and helps someone see what is happening inside the transmission and maybe helps them diagnosis a problem. If I said anthing to offend someone, sorry!
Bill Curlee
I hope this provides you with some more troubleshooting info.
Please let us know how you make out.
Bill Curlee
I took a look at the linked post and added some info that may help you resolve your notchey shift issue. Here is what I addes to the referenced post:
I found this post by accident and WOW,,,I am glad that I did! Thank you guys for all of the really great info!
I want to add a few thoughts that may help clear up a few things.
First thought. There are some people who are truely having a problem with "NOTCHY" shifting issue that may be different than what we are discussing with the feel of the shifter. I believe that they are NOT talking about the detent feel but the feel that you get from the synchros not allowing the driven and engageing gear to syncronize.
The fluid in my 98 MN6 wore out and I would get that "GRINDING" feel when shifting aggresively. It was like it would skip a few teeth on the synchro and then pop into gear. I caught it early and figured out was wrong. Just changing the fluid and adding Mobil 1 Synthetic ATF made a world of difference and resolved that issue.
Second thought. For those who venture into the world of the "Afrermarket Shifter" there are a couple of things to note:
-1. Some shifters have a large bolt or screw on the front and back of the shifter body. This bolt or screw is a stop. It adjust the throw of the shift lever. The T56 really doesn't need the stop bolt because the tranny has internal stops. If someone installed your shifter for you or if you installed it and the bolt was improperly adjusted (screwed too far in) the shift lever will not be able to move the shift fork far enough and this can cause the tranny to jump out of gear. If your tranny pops out of gear and your shifter has stops, back them out and see if that helps.
The forward bolt/screw effects 1st, 3rd, and 5th. The rear bolt/screw effects 2nd, 4th and 6th. You can just see the bolts on the aftermarket shifter on the right:
-2. When you remove your old OEM shifter, this is what you will see:
The rod with the loop in the center of it, is the shift rod. It moves forward and back and also moves in an arc (side to side) Sometimes this housing and the rod get dry or dirty and the rod can hang up. That can give you a stiff notchey shift feeling also. Lubricate the rod with lithium grease if it is dry and stiff. There is also a black plastic shoe on the end of the shift rod that fits in the loop in the shift rod. If that cap breaks or wears out, it can also cause the tranny to jump out of gear because the shifter can not fully engage the shift fork into gear.
As for the OEM shifter, it does NOT have any sort of centering springs in the shifter body. If you remove the OEM shifter from the shifter housing, the shift rod will flop around like a rag doll. The centering springs are internal to the transmission. Early C5's had very weak return springs that moved the lever from the 5-6 position back to the 3 N 4 position. Later C5 trannys had a slightly stronger spring to assist centering but it still sucks. Some aftermarket shifters have adjustable return springs that make centering very positive. My Kirban is one.
As for the Antivenom shift mod, the detent is most likely there to provide a positive feel to let the driver "KNOW" that he/she is in the gear selected. As for reducing the pressure of the detent ball with a washer or going all the way and installing a plug without a detent, I guess it all has to do with personal feel. Each gear has a set of dogs that set the slider gear in place when you engage that gear. My guess is that the detent ball just helps keep the shifter handle in the gear selection gate and gives you that "yea. it's in gear" feeling. I am not a T56 tranny expert either!
I hope all of this makes sense and helps someone see what is happening inside the transmission and maybe helps them diagnosis a problem. If I said anthing to offend someone, sorry!
Bill Curlee
I hope this provides you with some more troubleshooting info.
Please let us know how you make out.
Bill Curlee
Last edited by Bill Curlee; Nov 16, 2005 at 01:02 AM.
Thread Starter
Melting Slicks
Joined: May 2000
Posts: 2,974
Likes: 5
From: CenTex Texas
COOL! Thanks for the tips.
I'm about to start on an LG Header install, and while the car is up in the air i'm going to try two things - first change tranny fluid, and second bleed the clutch. If neither work then i'll give some of the other tips a try. I'll post back on my results.
Thanks for the tips. I'm about to start on an LG Header install, and while the car is up in the air i'm going to try two things - first change tranny fluid, and second bleed the clutch. If neither work then i'll give some of the other tips a try. I'll post back on my results.
Last edited by 97C5ENVY; Nov 15, 2005 at 11:13 PM.
