: Transmission AND Clutch Problems?

11-19-07, 03:20 AM
Hey v-family,

still loving my car, and have had relatively little trouble with it to-date as far as new problems go. But recently, some stuff has been bothering me with my transmission and clutch, and I am hoping you guys can help.

1- clutch
Sometimes when I am trying to agressively match a downshift, I'll rev match by blipping the gas pedal. When I do this, the clutch pedal sticks to the floor for like its being held there. It doesn't stay for a long time, but it is not a natural feeling. I've driven a lot of stick shift cars, and that feels...strange. I did some research, and I know there was a recall for a revised clutch. I brought this to my dealer's attention, and he said my car falls out side of that date range. Should I beleive him? I don't know how to express to him that this doesn't feel normal without him saying that I am thrashing on my car. I don't. I'm really good to it, but it encourages spirited driving and "rev matching on agressive downshift is not abuse if you do it right. Anyone else experience this problem of a sticky clutch pedal? Both those that are inside of and outside of the date range? Can someone take a look at my VIN and see if my dealer wasn't pulling my leg?

2- transmission
Sometimes when I go to grab 6th, the interlock that keeps me from going to reverse, is "missing." That's right. I can push it ALL The way over. At Freeway speeds. This is scary if you aren't paying attention, and my car will alert me with a "GRIND!" if I accidentally touch the reverse cog. Additionally, sometimes I CANNOT get it into 1st gear. No way no how. Well...correction..I can if I let out the clutch a little and let the car roll, or if I JAM it into first. This is also the case with reverse. Sometimes that is high resistance. Othertimes...it is like "butta." I realize this is a high-torque capacity transmission, but something seems...wrong. Particularly the fact that my "lockout" disapears. Is it on its way out? Has anyone else had any issues? How did you approach this and demonstrate this to your dealer?

My car is a 2005 with about 35,000 miles on it.

thanks in advance for your help!


11-19-07, 04:00 AM
Very common problems for all GM LSx vehicles w/ T56.

There is a sticky on the subject of the stuck clutch pedal on LS1Tech.
It's very informative.

The 1st gear thing is sometimes solved by doing a 2-1 shift.

The rev gear thing is probably worse for you, because of the rev grinds you did.

If your rev interlock is malfunctioning you need to get that fixed ASAP.

Call RPM Transmissions and see if they can shed some light on any of this.

Consider having them freshen up your trans.
Not under warranty, but worth it.

11-19-07, 10:04 AM
Try this:

M/T - Clutch Pedal Won't Go to Up Position at High RPM

Bulletin No.: 05-07-31-001A
Date: August 17, 2005
Clutch Pedal Does Not Return to Up Position During Shifts at High Engine RPMs (Inspect Date Code and Replace Clutch (http://www.alldatadiy.com/alldata/AFI~V10469316~C40138~R0~OD~N/0/108596970/110536423/110536424/110536428/34853741/34860071/34860772) Kit)

2005 Cadillac CTS-V
2005 Chevrolet Corvette, SSR

with Tremec T56 6-Speed Manual Transmission (RPOs M10, M12, MM6, MZ6)
This bulletin is being revised to add the RPO MZ6 6-Speed Manual Transmission. Please discard Corporate Bulletin Number 05-07-31-001 (Section 07 - Transmission/Transaxle).
Some customers may comment that while shifting at engine speeds greater then 6000 RPMs, the clutch pedal does not return to the up position. As the engine speed decreases, the clutch pedal will return to the up position.
It is possible that when the engine speed is greater than 6000 RPM and the clutch pedal is depressed, centrifugal loads on the clutch (http://www.alldatadiy.com/alldata/AFI~V10469316~C40138~R0~OD~N/0/108596970/110536423/110536424/110536428/34853741/34860071/34860772) diaphragm spring may be greater than the clutch return load from the diaphragm spring. This force created by RPM would be directionally opposite to the clutch bearing force, causing a near net zero or less than zero return force. As a consequence, the clutch pedal may be stuck at the bottom of travel at the floor. Once the engine speed reduces to less than 6000 RPM, spring return load dominates and the clutch pedal returns to normal function.
Inspect the clutch (http://www.alldatadiy.com/alldata/AFI~V10469316~C40138~R0~OD~N/0/108596970/110536423/110536424/110536428/34853741/34860071/34860772) date code and replace the clutch kit if built PRIOR to the following date code:
^4M21A/B/C for CTS-V and SSR
^4M13A/B/C for Corvette

1.Remove the transmission to inspect the date code on the clutch pressure plate (4). Refer to the applicable procedure below:
^Corvette - Clutch (http://www.alldatadiy.com/alldata/AFI~V10469316~C40138~R0~OD~N/0/108596970/110536423/110536424/110536428/34853741/34860071/34860772) Assembly Replacement
^CTS-V - Clutch (http://www.alldatadiy.com/alldata/AFI~V10469316~C40138~R0~OD~N/0/108596970/110536423/110536424/110536428/34853741/34860071/34860772) Assembly Replacement
^SSR - Clutch (http://www.alldatadiy.com/alldata/AFI~V10469316~C40138~R0~OD~N/0/108596970/110536423/110536424/110536428/34853741/34860071/34860772) Assembly Replacement
Important: The suspect clutches were built PRIOR to the following date codes:
^4M21A/B/C for CTS-V and SSR
^4M13A/B/C for Corvette

1. The date code is located on the pressure plate (http://www.alldatadiy.com/alldata/AFI~V10469316~C40138~R0~OD~N/0/108596970/110536423/110536424/110536428/34853741/34860071/34860772/34860952) cover as shown above.
2.Replace the clutch (http://www.alldatadiy.com/alldata/AFI~V10469316~C40138~R0~OD~N/0/108596970/110536423/110536424/110536428/34853741/34860071/34860772) kit (see part list below) if the date code on the pressure plate (http://www.alldatadiy.com/alldata/AFI~V10469316~C40138~R0~OD~N/0/108596970/110536423/110536424/110536428/34853741/34860071/34860772/34860952) is PRIOR to the date code as shown.

Parts Information
Warranty Information

11-19-07, 12:14 PM
I was just on the phone w/ McLeod discussing their twin disk clutch.

I found it interesting that they feel a Borg & Beck pressure plate is required for proper shifting performance above 5K RPM.
They feel the Diaphragm stype PP does not work well at high RPM.

It is well documented that the LSx community has been having lots of problems with high RPM shifting using a Diaphragm style PP.
I just joined that club myself.

I'm now definetly considering the Bork & Beck PP.
Anyone ever tried them?