Sometimes can't shift into 1st gear
Safety Car
Joined: Dec 2004
Posts: 4,276
Likes: 8
From: Tucson AZ
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15
Originally Posted by ALFA 1
I see this comment so much about brake pads being cheaper than a clutch, it deserves some comment. If you are downshifting, in part you use "engine braking" to slow the car, you do not (should not) be using a slipping clutch to do so. Engine braking is just that; you use the compression of the engine to slow, not the slip of a clutch. If it is also a braking situation, then you use heel and toe to match revs. The clutch's ability to slip (and consequently wear) is only there to make up for the errors you make in matching revs. You don't slip the clutch on routine upshifts do you? (On upshifts, matching revs is much more 'natural' since the engine speed falls on the momentary release of the throttle pedal) If you are wearing out your clutch prematurely, then you are not downshifting correctly. The point of matching revs on a gear change, in addition to smoothness and overall car control, is to have the input and output rotations at a similar speed so that the clutch does not have to slip.
In forty years I've never worn out a clutch, many cars with over 100,000 miles, some even bought used, and I always downshift through all gears while slowing. The reasoning is that you always want to be in the correct gear for whatever speed so that in unexpected situations you are never caught flatfooted in the wrong gear (or worse yet, coasting in neutral). Being in exactly the right gear may not be so important in a car as torquey as the C6, but it is still a good habit. I do double-clutch down, having learned on non-synchro gearboxes, but nowadays I use that old habit as a timing aid; modern gearboxes don't really require it.
As for keeping the clutch depressed at a stop, I never do it for the sake of throw-out bearing life.
Not being able to engage first is not uncommon in any manual; by chance the teeth are just not lined up properly. As others have suggested, temporarily selecting another gear usually solves this, but simply depressing and releasing the clutch without even moving the gearshift often works too.
Hope this instigates a lively discussion and not just flames.
George
In forty years I've never worn out a clutch, many cars with over 100,000 miles, some even bought used, and I always downshift through all gears while slowing. The reasoning is that you always want to be in the correct gear for whatever speed so that in unexpected situations you are never caught flatfooted in the wrong gear (or worse yet, coasting in neutral). Being in exactly the right gear may not be so important in a car as torquey as the C6, but it is still a good habit. I do double-clutch down, having learned on non-synchro gearboxes, but nowadays I use that old habit as a timing aid; modern gearboxes don't really require it.
As for keeping the clutch depressed at a stop, I never do it for the sake of throw-out bearing life.
Not being able to engage first is not uncommon in any manual; by chance the teeth are just not lined up properly. As others have suggested, temporarily selecting another gear usually solves this, but simply depressing and releasing the clutch without even moving the gearshift often works too.
Hope this instigates a lively discussion and not just flames.
George
Jim
Advanced
Joined: Nov 2004
Posts: 50
Likes: 9
From: Plano, TX
Originally Posted by SpinMonster
Also, one of the guys said they have the Z51 with the MN6. This transmission is not an MN6.
Hmm... lemmie look:
Pics of the transmission in my Z51 optioned C6.
Picture of a T56 from an F-body, bolted directly to an LS1 engine, in my garage.
So... although I haven't removed one personally from a C6, the picture of the transmission in my C6 sure looks like a T56.... has six speeds. Could it be a T56?
Now... does the Z51 T56 manual have different gearing than the base C6 T56 manual? That's a different issue.
OK. Sorry to be a smart *** today. It's late on Friday...
Last edited by fair; May 6, 2005 at 05:33 PM.
Le Mans Master
Joined: Nov 2004
Posts: 7,242
Likes: 8
I too don't understand the comment "it's not a MN6". I have had the same problem getting into first; frankly, it's a little embarrasing. Everyone is looking at this cool Vette, and then I'm fumphering around with the gear selector - it looks like I can't drive a stick!
Tech Contributor
Joined: Mar 2003
Posts: 12,094
Likes: 197
From: Colorado Springs, CO
St. Jude Donor '08-'09-'10-'11
Hey not everyone is up on GM part numbers so....
It isn't necessary to show pictures with wise-azz remarks like 'it looks like a T56 tremec'....I didnt say it wasn't a T56. For the record I switched my C5 transmission MN6 with an M12.
The Z06 has the same transmission as the coupe 6-speed from 2001 through 2004 right?...wrong....Yes it is a T56, yes it is a 6-speed, yes its a tremec. THE Z51 t56 IS NOT OPTION CODE mn6
The transmission for the standard C5 AND C6 is the MN6....it has the standard gear ratios no change there. However while the Z06 had a 6-speed, also a tremec T56, the code wasn't the MN6 but rather the M12 due to the gear ratio changes. Now that follows that the gear ratios in the Z51 are not the same as the standard C6 right? For the record there were 3 different codes used for T56 transmissions in the last 5 years.
I think I went far enough here....
Oh wait, what was that....
It isn't necessary to show pictures with wise-azz remarks like 'it looks like a T56 tremec'....I didnt say it wasn't a T56. For the record I switched my C5 transmission MN6 with an M12.
The Z06 has the same transmission as the coupe 6-speed from 2001 through 2004 right?...wrong....Yes it is a T56, yes it is a 6-speed, yes its a tremec. THE Z51 t56 IS NOT OPTION CODE mn6
The transmission for the standard C5 AND C6 is the MN6....it has the standard gear ratios no change there. However while the Z06 had a 6-speed, also a tremec T56, the code wasn't the MN6 but rather the M12 due to the gear ratio changes. Now that follows that the gear ratios in the Z51 are not the same as the standard C6 right? For the record there were 3 different codes used for T56 transmissions in the last 5 years.
I think I went far enough here....
Oh wait, what was that....
Last edited by SpinMonster; May 7, 2005 at 04:21 AM.
Tech Contributor
Joined: Mar 2003
Posts: 12,094
Likes: 197
From: Colorado Springs, CO
St. Jude Donor '08-'09-'10-'11
Originally Posted by fair
Huh? I don't mean to sound like a jackass... but what the heck are you talking about?? How do you figure the Z51 doesn't have the T56 manual 6 speed (MN6 option code)?
Whoa, I never said it wasn't a T56....I just said it wasn't an MN6
The Z06 has a T56 but it is option code M12
Hmm... lemmie look:
Pics of the transmission in my Z51 optioned C6.
Picture of a T56 from an F-body, bolted directly to an LS1 engine, in my garage.
So... although I haven't removed one personally from a C6, the picture of the transmission in my C6 sure looks like a T56.... has six speeds. Could it be a T56?
Yes it is a T56 but there are three of them.
Now... does the Z51 T56 manual have different gearing than the base C6 T56 manual? That's a different issue.
That is the very core of your mistake...the T56 in the Z06 was the M12 because of different gearing.
OK. Sorry to be a smart *** today. It's late on Friday...
Whoa, I never said it wasn't a T56....I just said it wasn't an MN6
The Z06 has a T56 but it is option code M12
Hmm... lemmie look:
Pics of the transmission in my Z51 optioned C6.
Picture of a T56 from an F-body, bolted directly to an LS1 engine, in my garage.
So... although I haven't removed one personally from a C6, the picture of the transmission in my C6 sure looks like a T56.... has six speeds. Could it be a T56?
Yes it is a T56 but there are three of them.
Now... does the Z51 T56 manual have different gearing than the base C6 T56 manual? That's a different issue.
That is the very core of your mistake...the T56 in the Z06 was the M12 because of different gearing.
OK. Sorry to be a smart *** today. It's late on Friday...
OK so if gearing was the issue that was different about the T56 for the Z06 and it warranted a different code name and part number, what do you think happened when the T56 was regeared for the Z51 C6?.....a new code MZ6 and part number. See the attached memo for a mention on this code near the top of the page it was the first C6 problem: http://www.corvetteactioncenter.com/....php?qstId=536
If that wasn't enough for you then click on this link for the list of options and codes that came with this Z51 and the code on its 6 speed transmission: http://www.corvettenet.com/vehicle_d...ckNumber=51373
...And since you like to be thorough, click on this and read the section on new options for the C6:
http://www.chazcone.com/corvette/det...004/slides.htm
or GM's list of all transmissions: http://www.vibratesoftware.com/html_...nsmissions.htm
ok now lemee see--summary: regular production option codes (RPO):
T56 in C5 base: MN6
T56 in Z06 : M12
T56 in C6 base :MN6 some articles refer to MM6
T56 in C6 Z51: MZ6
Judging from the long involved post with pictures and all, you put an awful lot of work into trying to rub things in people's faces.
Last edited by SpinMonster; May 7, 2005 at 08:09 PM.
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Tech Contributor
Joined: Mar 2003
Posts: 12,094
Likes: 197
From: Colorado Springs, CO
St. Jude Donor '08-'09-'10-'11
Originally Posted by CRVETTE
had the same issue with C5's
Instructor
Joined: Aug 2004
Posts: 182
Likes: 0
From: Terra Ceia FL
I have MZ6 and have the same problem. I am at 11,500 miles and it is not getting any better. I am in flat Florida, so at a stop light I generally put it in neutral and take my foot off the clutch. It frequently will not go back into first. I first put it in 2nd and then try 1st again. If it does not work I just go back into 2nd and start from there. More frequestly lately I just start in 2nd. I also occaisionally shift into 1st right before I come to a complete stop, allowing the syncros to work.
All that being said, it is an annoying problem.
All that being said, it is an annoying problem.
Tech Contributor
Joined: Mar 2003
Posts: 12,094
Likes: 197
From: Colorado Springs, CO
St. Jude Donor '08-'09-'10-'11
I tried this lil' experiment today:
When slowing to come to a stop, let the car slow in gear until it is near 1k rpm's without taking it out of gear and coasting to a stop. It never gave me a problem going into first when I did this. When I coasted, it did it 75% of the time.
When slowing to come to a stop, let the car slow in gear until it is near 1k rpm's without taking it out of gear and coasting to a stop. It never gave me a problem going into first when I did this. When I coasted, it did it 75% of the time.
Team Owner
Joined: Dec 2002
Posts: 32,074
Likes: 296
From: San Francisco CA
Those ladies will have less problems than you and leave you standing still
Originally Posted by NineBall
no thanks! automatic sports cars are for ladies 
Tony
Tony
Melting Slicks
Joined: Jan 2005
Posts: 2,263
Likes: 1
From: Houston Texas
Originally Posted by ALFA 1
I see this comment so much about brake pads being cheaper than a clutch, it deserves some comment. If you are downshifting, in part you use "engine braking" to slow the car, you do not (should not) be using a slipping clutch to do so. Engine braking is just that; you use the compression of the engine to slow, not the slip of a clutch. If it is also a braking situation, then you use heel and toe to match revs. The clutch's ability to slip (and consequently wear) is only there to make up for the errors you make in matching revs. You don't slip the clutch on routine upshifts do you? (On upshifts, matching revs is much more 'natural' since the engine speed falls on the momentary release of the throttle pedal) If you are wearing out your clutch prematurely, then you are not downshifting correctly. The point of matching revs on a gear change, in addition to smoothness and overall car control, is to have the input and output rotations at a similar speed so that the clutch does not have to slip.
In forty years I've never worn out a clutch, many cars with over 100,000 miles, some even bought used, and I always downshift through all gears while slowing. The reasoning is that you always want to be in the correct gear for whatever speed so that in unexpected situations you are never caught flatfooted in the wrong gear (or worse yet, coasting in neutral). Being in exactly the right gear may not be so important in a car as torquey as the C6, but it is still a good habit. I do double-clutch down, having learned on non-synchro gearboxes, but nowadays I use that old habit as a timing aid; modern gearboxes don't really require it.
As for keeping the clutch depressed at a stop, I never do it for the sake of throw-out bearing life.
Not being able to engage first is not uncommon in any manual; by chance the teeth are just not lined up properly. As others have suggested, temporarily selecting another gear usually solves this, but simply depressing and releasing the clutch without even moving the gearshift often works too.
Hope this instigates a lively discussion and not just flames.
George
In forty years I've never worn out a clutch, many cars with over 100,000 miles, some even bought used, and I always downshift through all gears while slowing. The reasoning is that you always want to be in the correct gear for whatever speed so that in unexpected situations you are never caught flatfooted in the wrong gear (or worse yet, coasting in neutral). Being in exactly the right gear may not be so important in a car as torquey as the C6, but it is still a good habit. I do double-clutch down, having learned on non-synchro gearboxes, but nowadays I use that old habit as a timing aid; modern gearboxes don't really require it.
As for keeping the clutch depressed at a stop, I never do it for the sake of throw-out bearing life.
Not being able to engage first is not uncommon in any manual; by chance the teeth are just not lined up properly. As others have suggested, temporarily selecting another gear usually solves this, but simply depressing and releasing the clutch without even moving the gearshift often works too.
Hope this instigates a lively discussion and not just flames.
George
Race Director
Joined: Oct 2004
Posts: 10,516
Likes: 2
From: Virginia Bch VA
Cruise-In VI Veteran
Cruise-In VII Veteran
St. Jude Donor '06
Just cycle the clutch, push the clutch in and out. It will go in then.
I've started to put it in 1st as I'm coming to a stop. That really works. And @ 9950miles it hardly ever happens anymore
I've started to put it in 1st as I'm coming to a stop. That really works. And @ 9950miles it hardly ever happens anymore
Advanced
Joined: Nov 2004
Posts: 75
Likes: 0
From: Longview TX
1st gear
Guys, I have had the same problem with my 99 c5. I looked into seeing if it had any wear on my trany first, didn't find any. I was talking to a speed shop locally and they told me to drain all the trany fluid out, and fill it full of gm synchromesh. No regular atf. I had my buddy do the same thing to his 99 c5, we both swear that it helped at least 60%. We were very surprised. That was very annoying for me not be able to put it in 1st gear when I wanted to. i have also noticed that when the synchromesh warms up a little more, it is even better. I hope this helps.
Advanced
Joined: May 2005
Posts: 65
Likes: 0
From: Miami Beach Florida
2nd gear also
I have the same problem in 1st and often shift into other gears to get it resolved. There have been a couple of times that I have a problem down shifting into 2nd. Has anyone else experienced this??
Safety Car
Joined: Jun 2004
Posts: 4,430
Likes: 81
From: Whidbey Island WA
Jeez, like most other cars just put it into first as you are almost rolled to a stop. Then kick it out if your waiting for a light. It will go back as long as you dont allow the car to roll. You can also put it in second and just give it a little nudge with the clutch and then it will go right in. Also you can often double clutch it and it will go in. Further you can usually just put it into another gear and it will usually go right in. All of these things are common ways to get it done with any tranny. Notice I say common because if you drive sticks your going to find that this is common. Driving a stick requires you be involved in the process and develop such skills as needed to shift. They have quirks. This is part of the fun and what makes them a more entertaining drive than an auto. If you are having trouble getting it into first the problem is most likely that you need to adjust the nut holding the shifter.
Advanced
Joined: May 2005
Posts: 65
Likes: 0
From: Miami Beach Florida
Originally Posted by crabman
Jeez, like most other cars just put it into first as you are almost rolled to a stop. Then kick it out if your waiting for a light. It will go back as long as you dont allow the car to roll. You can also put it in second and just give it a little nudge with the clutch and then it will go right in. Also you can often double clutch it and it will go in. Further you can usually just put it into another gear and it will usually go right in. All of these things are common ways to get it done with any tranny. Notice I say common because if you drive sticks your going to find that this is common. Driving a stick requires you be involved in the process and develop such skills as needed to shift. They have quirks. This is part of the fun and what makes them a more entertaining drive than an auto. If you are having trouble getting it into first the problem is most likely that you need to adjust the nut holding the shifter.
Just for your reference - My last car is a porsche 911 so I am very familiar with driving a manual 6 sports car. I never experienced any of the problems that I am having with the vette. I really love this car but I find it very annoying to have problems getting it into both 1st and second. Especially since it has happened several times when I was downshifting into 2nd and needed to accelerate. There have also been times when I have to shift into 3rd or 4th and then into 1st because it won't go into 2nd either..
Safety Car
Joined: Dec 2000
Posts: 4,329
Likes: 10
From: Cape Coral fl
Originally Posted by SpinMonster
Sorry?
OK so if gearing was the issue that was different about the T56 for the Z06 and it warranted a different code name and part number, what do you think happened when the T56 was regeared for the Z51 C6?.....a new code MZ6 and part number. See the attached memo for a mention on this code near the top of the page it was the first C6 problem: http://www.corvetteactioncenter.com/....php?qstId=536
If that wasn't enough for you then click on this link for the list of options and codes that came with this Z51 and the code on its 6 speed transmission: http://www.corvettenet.com/vehicle_d...ckNumber=51373
...And since you like to be thorough, click on this and read the section on new options for the C6:
http://www.chazcone.com/corvette/det...004/slides.htm
or GM's list of all transmissions: http://www.vibratesoftware.com/html_...nsmissions.htm
ok now lemee see--summary: regular production option codes (RPO):
T56 in C5 base: MN6
T56 in Z06 : M12
T56 in C6 base :MN6 some articles refer to MM6
T56 in C6 Z51: MZ6
Judging from the long involved post with pictures and all, you put an awful lot of work into trying to rub things in people's faces.
OK so if gearing was the issue that was different about the T56 for the Z06 and it warranted a different code name and part number, what do you think happened when the T56 was regeared for the Z51 C6?.....a new code MZ6 and part number. See the attached memo for a mention on this code near the top of the page it was the first C6 problem: http://www.corvetteactioncenter.com/....php?qstId=536
If that wasn't enough for you then click on this link for the list of options and codes that came with this Z51 and the code on its 6 speed transmission: http://www.corvettenet.com/vehicle_d...ckNumber=51373
...And since you like to be thorough, click on this and read the section on new options for the C6:
http://www.chazcone.com/corvette/det...004/slides.htm
or GM's list of all transmissions: http://www.vibratesoftware.com/html_...nsmissions.htm
ok now lemee see--summary: regular production option codes (RPO):
T56 in C5 base: MN6
T56 in Z06 : M12
T56 in C6 base :MN6 some articles refer to MM6
T56 in C6 Z51: MZ6
Judging from the long involved post with pictures and all, you put an awful lot of work into trying to rub things in people's faces.
I think "fair" was just owned!!!