Transmission Question

[SSTibet]

I have a 6 speed ZF transmission in my 95 coupe. There are no problems what so ever with 1 - 6 forward gears. However it is sometimes difficult to shift to rear (I have to really push it hard) and sometimes it throws out of the rear with a grinding noise... Scary s..t !!!

Any reason why this may be happening ???

Cheers,

Selim

 

[Ken]

I don't know anything about the ZF internals, but it sounds to me like that is exactly what you're going to have to do Selim, get into the inside of the transmission.

It's either an adjustment problem (it's an internal rail shifter design, meaning the adjustment problem is inside the transmission rather than in external linkage) or it's a more complicated problem in the gear sets themselves.

Hopefully we have some ZF experts here who'll be able to help you. Good luck!

 

[89z51l98]

On mine that tiny little allen set screw in the back of the shifter had started to come lose and wasn't pulling the reverse lockout lever all the way up...

I have a 6 speed ZF transmission in my 95 coupe. There are no problems what so ever with 1 - 6 forward gears. However it is sometimes difficult to shift to rear (I have to really push it hard) and sometimes it throws out of the rear with a grinding noise... Scary s..t !!!

Any reason why this may be happening ???

Cheers,

Selim

 

[FX GS]

Selim, sounds like the clutch slave cylinder is on it's way out. Might as well replace the clutch master cylinder at the same time because usually, when one of these parts fails, the other one is not far behind.

 

[SSTibet]

Now I am even more scared... So this may be a clutch problem not a transmission? Or both???

The throwing out of the reverse gear is not always happening... Sometimes it works like a butterfly and other times I have to really watch it.

So??? Where do I go from here folks?

 

[FX GS]

Now I am even more scared... So this may be a clutch problem not a transmission? Or both???
The throwing out of the reverse gear is not always happening... Sometimes it works like a butterfly and other times I have to really watch it.
So??? Where do I go from here folks?

Have you checked the level of fluid in your clutch master cylinder? It could be as simple as just low fluid causing your problem.
If it it the slave cylinder, it's nothing major, however I don't know how readily available that part would be where you live.
I don't feel as if it is a problem with the transmission or clutch directly, but in the hydraulic system, which is something that usually is an "easy" fix

Go to www.zfdoc.com. There is a wealth of info on this site.

Good luck

 

[SSTibet]

This reverse gear problem (I think) mostly happens at cold start up, when l leave my garrage by backing up the car (don't please recommend to park the car in the other direction ) Maybe it is the oil level. I love this probability. After all the car is 35K miles and I belive it should not have mechanical problems yet. Yes?


Selim

 

[SSTibet]

Coming back home from work today I did a number of tests. I read the replies here and visited www.zfdoc.com of course before doing the following. Now, remember the car has been sitting still for 4 days in a closed place, but it is still cold around (a sweater is highly recommended...).

1. Before starting the car and with the clutch pedal fully depressed shifted from 1 to R and back to 1. Did this a few times and observed no obvious problems.

2. Started the car, pulled the parking brake. Clutch pedal fully depressed, shift from 1 to R and back to 1. Did this a few times. No problems. Rear lights of the car comes on.

3. Tried shifting into R without depressing the clutch pedal. Sounds stupid I know, the shifter goes all the way to the right but cannot move further down. Gave up pulling the stick to R due to lack of a sledge hammer at that point. Rear lights came on though :J

4. Short of breaking the tranny, started trying how far I should depress the clutch pedal to engage from N to R successully. :naughty: To my very surprise I had to depress the pedal for like 2/3 of the way down to engage into R :dance

After doing all of the above I moved the car back and forth a few times and did it beautifully.

It is this funny feeling that I have when I shift to reverse. Push the shifter past the 5/6 and right at that spot there is a point that I need to catch before pulling the stick down towards R position. If I catch that point it goes into R okay. And if I cannot get it? Arghhhhh.... ad

So what do you think?

 

[Vettelt193]

Coming back home from work today I did a number of tests. I read the replies here and visited www.zfdoc.com of course before doing the following. Now, remember the car has been sitting still for 4 days in a closed place, but it is still cold around (a sweater is highly recommended...).

1. Before starting the car and with the clutch pedal fully depressed shifted from 1 to R and back to 1. Did this a few times and observed no obvious problems.

2. Started the car, pulled the parking brake. Clutch pedal fully depressed, shift from 1 to R and back to 1. Did this a few times. No problems. Rear lights of the car comes on.

3. Tried shifting into R without depressing the clutch pedal. Sounds stupid I know, the shifter goes all the way to the right but cannot move further down. Gave up pulling the stick to R due to lack of a sledge hammer at that point. Rear lights came on though :J

4. Short of breaking the tranny, started trying how far I should depress the clutch pedal to engage from N to R successully. :naughty: To my very surprise I had to depress the pedal for like 2/3 of the way down to engage into R :dance

After doing all of the above I moved the car back and forth a few times and did it beautifully.

It is this funny feeling that I have when I shift to reverse. Push the shifter past the 5/6 and right at that spot there is a point that I need to catch before pulling the stick down towards R position. If I catch that point it goes into R okay. And if I cannot get it? Arghhhhh.... ad

So what do you think?

what do you mean by catch a point? if you move the shifter too far to the right, it won't drop in to R?

 

[SSTibet]

what do you mean by catch a point? if you move the shifter too far to the right, it won't drop in to R?

First lets agree on "too far", okay? I push the shifter to the right beyond the 5/6. And there is of course a limit how far it will go. You can not push it any further than that anyways.

At that limit I pull the shifter down to engage in Reverse (am I doing this wrong?). It is at the end of the "right hand movement of the shifter" where I feel I have to maneuver the shifter in the backward motion. I may have to do a slight circular motion / shaking up and down a just a bit (or a very slight forward and then backward) at that point before pulling it down to R. I am telling you, it is a strange and funny feeling... May be I am exeggarating this issue. I dont know :cry

Tell me, how do you shift into Reverse? I know it is mostly by intuition, and one does not follow every motion he / she does while driving a car. But give me any hints you can...

Cheers,

Selim

 

[Vettelt193]

First lets agree on "too far", okay? I push the shifter to the right beyond the 5/6. And there is of course a limit how far it will go. You can not push it any further than that anyways.

At that limit I pull the shifter down to engage in Reverse (am I doing this wrong?). It is at the end of the "right hand movement of the shifter" where I feel I have to maneuver the shifter in the backward motion. I may have to do a slight circular motion / shaking up and down a just a bit (or a very slight forward and then backward) at that point before pulling it down to R. I am telling you, it is a strange and funny feeling... May be I am exeggarating this issue. I dont know :cry

Tell me, how do you shift into Reverse? I know it is mostly by intuition, and one does not follow every motion he / she does while driving a car. But give me any hints you can...

Cheers,

Selim

Can you feel the 'crash through'? In a nutshell, to get it past 5/6 it should take more effort than to get the shifter to 5/6. (on earlier C4's they had the lock-out, I am not sure why they changed it). Assuming you are getting through the 'crash through', it should just drop straight down to reverse....

Now... if you are getting a 'grinding' when trying to get it into reverse, you could have a synchro problem. Mine does this somewhat frequently, although it is a million times better after my new clutch, new fluid, and new slave cyl. (only 1 time since the new stuff -- although only a week has gone by)

Usually with late C4's (without the manual lock-out for R), Reverse problems are related to missing a shift into 6th and grinding into R... the master/slave could be bad, and so could the tranny fluid. (what kind of tranny fluid do you run?)

 

[NC2Stay]

Adding my two cents worth, my 6 speed '95 is not "easy" to shift into reverse. It seems less "natural" than other cars I have had - you have to think about it a little more, and I always make sure the clutch is fully engaged.

But at no point did I feel that it was failing in any way - just chalked it up to the way the tranny works.

Bob

 

[SSTibet]

Bob,

Thx for the insight. This is my first Corvette, and I never drew a manual American car before. So, it may be my habits combined with the car's leading to this discomfort.

But anyways, I will have my mechanic check it at my first visit to his shop.

Thanks again,

Selim

 

[SSTibet]

Can you feel the 'crash through'? In a nutshell, to get it past 5/6 it should take more effort than to get the shifter to 5/6. (on earlier C4's they had the lock-out, I am not sure why they changed it). Assuming you are getting through the 'crash through', it should just drop straight down to reverse....

Now... if you are getting a 'grinding' when trying to get it into reverse, you could have a synchro problem. Mine does this somewhat frequently, although it is a million times better after my new clutch, new fluid, and new slave cyl. (only 1 time since the new stuff -- although only a week has gone by)

Usually with late C4's (without the manual lock-out for R), Reverse problems are related to missing a shift into 6th and grinding into R... the master/slave could be bad, and so could the tranny fluid. (what kind of tranny fluid do you run?)

Yes, I can feel the crash through to get it past the 5/6. When the problem arises is after this point. Sometimes it goes into reverse very smoothly. And some other times it has to be worked on.

Sometimes smoothly and sometimes more difficult I get it into the reverse gear. That is part of the problem. If you read one of my posts above, you will notice that I have to depress the clutch pedal ony 2/3 of the way down to engage into R. Smooth or not, that much depression is being enough.

So, the grinding does not happen when I am putting it into reverse. But rather, when I think it is already in R and when I start relasing the clutch pedal. I hear the grinding noise telling me it is not quite there...

 

[Vettelt193]

So, the grinding does not happen when I am putting it into reverse. But rather, when I think it is already in R and when I start relasing the clutch pedal. I hear the grinding noise telling me it is not quite there...

\

That is what happens to me sometimes too.

I do one of two things....

One is: Once I 'think' it is in, I continue to apply pressure to the stick in the reverse direction and SLOWLY let the clutch pedal out. If it isn't quite in, instead of getting a grind by letting the clutch out at your normal rate, slowly letting it out makes it drop right in.

The other is shifting from N to 1 to R. If I am in 1st, I go 1 - N - 1 - R. that seems to do it too. If yours doesn't like first, try a different gear, like 3rd. It seems to 'get the synchros going'

 

[SSTibet]

Vettelt,

I think it mostly due to my inexperience with American muscle. And I have not driven a manual car for the last 4 years or so. I will see if the problems persists. Hope it does not.

What do you mean by "It seems to 'get the synchros going'"??? Remember I am a Turkish person and do not have as good command of English as you folks do

Cheers & have a great weekend

Selim