Viper Clutch System 101

[Jack B]

Let me emphasize that I do not claim to be an expert on the viper clutch , but, on the other hand I don't think there are many of those around. I was having some issues with my clutch and started asking questions and found that I was not getting any answers so I decided to dissect the slave and take some dimensions.

I going to post the pictures and operating sequence tonight. I will follow up with some dimensional data later in the week.

I will start on the left side and explain my numbering system:

Line #4 - that line is the bottom of the rubber ram that forces the throwout bearing into the clutch. The area below the #4 line is filled with hydraulic fluid. In other words that is where the ram sat in my car when the clutch was not depressed.

Line #3 - that is the actual metallic follower that sits on top of the rubber ram. It is the piece that makes contact with transmission side of the throwout bearing. It also has an internal rubber seal that aids in the sealing process.

Line #2 - this is the actual travel distance the the slave delivers. The throwout bearing started at Line #3 and traveled to Line #2 when the clutch was depressed.

Line #1- this is the maximum the slave can travel without losing fluid, if you go beyond Line #1 you will loose the pedal.

This is the transmission side of the throwout bearing. Ignore the brass rod, that is my way of standing up the ram and follower. The sequence is:

#6 follower - this is what contacts the throwout bearing on the clutch side.It also rests on top of the the rubber ram on the transmission side. This is also #3 in the earlier picture. I indicate it as the metal follower, but, it is actually comprised of two thin metallic rings with a seal on the inner diameter.

#5 hydraulic ram - the bottom of this sits at line #4 in the first picture. The metal follower sits on top of the ram.

More to come ...........

 

[Camfab]

Jack what was your issue again? Incomplete clutch disengagement or hanging up? Thanks for the detail pics, I'm all eyes and ears (actually in this case...all eyes).

 

[Jack B]

Jack what was your issue again? Incomplete clutch disengagement or hanging up? Thanks for the detail pics, I'm all eyes and ears (actually in this case...all eyes).

The transmission would not allow you to shift fast. It wasn't real noticeable when you shifted slowly, but, it would totally lock out a fast shift. I knew the input shaft was turning, therefore, locking me out. It is easy to tell if the input shaft is turning (a problem) , rev the car to 2000 rpm in neutral, but, have the shifter between first and second. Push the clutch in quickly and immediately try to shift in 1st gear. In you feel resistance go to step two. Do the same sequence, but, wait for five seconds to shift into first gear. If you felt resistance in case one and not in case two, the input shaft was still spinning in case one, but, not in case two.

The only causes for this are:

1. Bad pilot bearing (not likely)

2. Warped disk or flywheel

3. Bad spline on input shaft (not likely)

4. Too much rotating weight (heavy disk)

In my case I had changed to a full metallic disk and it weighed 8.1 lbs. To put this into prospective, my old Centerforce was 5 lbs 13 oz. My guess is the stock clutch disk is around 5 lbs. I solved the problem by going to a Petal style metallic disk. It weighed 4 lbs 4 oz.

Keep in mind this was a shifting issue strictly created by a heavy disk. Shifting issues can also be clutch related if the disk swells due to slippage. Once it swells it can cause the input shaft to rotate.There is not a lot of space between engaged and not engaged. That is why a metallic clutch may solve some shifting issues.

 

[Viper Specialty]

A worn synchronizer face can also cause a harder/impossible faster shifts as it will be incapable of spinning up/down the rotational weight in a certain time. Also, the engaugement teeth of the hub slider/gear, if worn into a curve or flat spot rather than a point, can also cause you to be "locked" out of a gear on a rapid shift.

I would advise checking those if you are going through the hassle.

Other than that, it could be a combination of issues; slight wear, and a heavy, mildly warped disk.

If your input shaft will continue to spin with your foot on on the clutch while in nuetral, even a little, I would look at the clutch assembly. If it stops immediately, it is unlikely it is causing enough drag to make a shift slow. Other than that, a delayed disengaugement may be worth a look, though this would likely be the result of a part of the case or slave flexing under stress, or an inherent engaugement problem with your combination.

I would try looking at the common weak points before reinventing the wheel...

 

[RAYSIR]

I agree with Viper Specialty. Sounds like syncro or thick gear oil to me. The fact that it doesn't grind between shifts and shifts leaves out the hydralics.

 

[RobZilla]

Does pumping the clutch from time to time while in nuetral and stopped wear out the pressure plate, or decrease the life of your clutch system ????

Z

 

[RAYSIR]

Does pumping the clutch from time to time while in nuetral and stopped wear out the pressure plate, or decrease the life of your clutch system ????

Z

Rob, I don't think your leg could hold up long enough for that to happen. I think it would wear out the master cylinder or slave first. BUT, the worst part for wear on all these parts is not using them and sitting and having the seals get dried and hard.

 

[RobZilla]

That should just about answer it.... I know I ride with a guy that does it often. I do it from time to time, but our cars never sit for more than a week or two at a time. We live in sunny Florida where we can drive all year round

Thanks for the tip.

Zilla

 

[Jack B]

A worn synchronizer face can also cause a harder/impossible faster shifts as it will be incapable of spinning up/down the rotational weight in a certain time. Also, the engaugement teeth of the hub slider/gear, if worn into a curve or flat spot rather than a point, can also cause you to be "locked" out of a gear on a rapid shift.

I would advise checking those if you are going through the hassle.

Other than that, it could be a combination of issues; slight wear, and a heavy, mildly warped disk.

If your input shaft will continue to spin with your foot on on the clutch while in nuetral, even a little, I would look at the clutch assembly. If it stops immediately, it is unlikely it is causing enough drag to make a shift slow. Other than that, a delayed disengaugement may be worth a look, though this would likely be the result of a part of the case or slave flexing under stress, or an inherent engaugement problem with your combination.

I would try looking at the common weak points before reinventing the wheel...

Dan:

Please read a little closer, it was a delayed disengagement and it has been solved, the disk was too heavy, the inertia didn't allow the the input shaft to slow down quick enough. With no change other than going from a 8+ lb disk to a 4 lb disk solved it. It was never a transmission issue, this was a new racing rebuild by john Dinoto, there aren't many that do a better job on the T56.

 

[Jack B]

Does pumping the clutch from time to time while in nuetral and stopped wear out the pressure plate, or decrease the life of your clutch system ????

Z

Like everyone has indicated it shouldn't matter. The throwout bearing is always in contact with the fingers. The fingers on the clutch are not slipping against the bearing, the inner bearing race is spinning. If you see a polished set of fingers, the bearing is starting to go.

 

[Viper Specialty]

Jack:

Hmm... I have to be honest, the post is a little misleading.

I thought you were still having a problem, not that it was solved? From all of the measurements up top, it looks like you are still looking for some info, or are you just making an information post?

Is there two parts to this or something...?

 

[Nadine UK GTS]

Hi Jack, I've been waiting to see this post. LOL, I'm not the only one that disects the OE slave then!

 

[Jack B]

Jack:

Hmm... I have to be honest, the post is a little misleading.

I thought you were still having a problem, not that it was solved? From all of the measurements up top, it looks like you are still looking for some info, or are you just making an information post?

Is there two parts to this or something...?

Dan:

sorry about the confusion, most people do not pay attention to the slave cylinder and I was in a position to offer some good data, that is why I posted the pics. I did rule out the slave, but, there are some dimensions (just can't find my notes) that I want to post . There is a a sweet spot where the fingers should be, that is the one dimension that I feel is important. What is really disconcerting is that the clutch suppliers do not even know that dimension.

The second reason for the post, is the fact that I found such a range in disk weights. This manifested itself into a performance issue. There is no doubt that the 8 lb+ disk hampered shifting. It is not actually the weight, but, the polar moment of inertia. Weight is part of that calculation, but, so is the location of the weight. That is part of the reason the petal style disks have an advantage, especially in a large diameter disk. Once again, sorry for the confusion.

 

[MoparMan]

The transmission would not allow you to shift fast. It wasn't real noticeable when you shifted slowly, but, it would totally lock out a fast shift. I knew the input shaft was turning, therefore, locking me out. It is easy to tell if the input shaft is turning (a problem) , rev the car to 2000 rpm in neutral, but, have the shifter between first and second. Push the clutch in quickly and immediately try to shift in 1st gear. In you feel resistance go to step two. Do the same sequence, but, wait for five seconds to shift into first gear. If you felt resistance in case one and not in case two, the input shaft was still spinning in case one, but, not in case two.

The only causes for this are:

1. Bad pilot bearing (not likely)

2. Warped disk or flywheel

3. Bad spline on input shaft (not likely)

4. Too much rotating weight (heavy disk)

In my case I had changed to a full metallic disk and it weighed 8.1 lbs. To put this into prospective, my old Centerforce was 5 lbs 13 oz. My guess is the stock clutch disk is around 5 lbs. I solved the problem by going to a Petal style metallic disk. It weighed 4 lbs 4 oz.

Keep in mind this was a shifting issue strictly created by a heavy disk. Shifting issues can also be clutch related if the disk swells due to slippage. Once it swells it can cause the input shaft to rotate.There is not a lot of space between engaged and not engaged. That is why a metallic clutch may solve some shifting issues.

Would the issues with the transmission not allowing you to shift fast occur on all gears or just one or two? My tranny very intermittently does this on the 2nd to 3rd shift when done at WOT. However, the symptom in my case is that the shift goes as normal - clutch in, push to 3rd gear gate, clutch out, however when the problem occurs, the car is in neutral, not 3rd. This happens maybe once every 20 or 30 WOT shifts from 2nd to 3rd. This is my second Viper and I've made well over 50 passes on a dragstrip between the two not to mention "exhibitions" on the street, so I'm no stranger to the T56.

 

[Viper Specialty]

Would the issues with the transmission not allowing you to shift fast occur on all gears or just one or two? My tranny very intermittently does this on the 2nd to 3rd shift when done at WOT. However, the symptom in my case is that the shift goes as normal - clutch in, push to 3rd gear gate, clutch out, however when the problem occurs, the car is in neutral, not 3rd. This happens maybe once every 20 or 30 WOT shifts from 2nd to 3rd. This is my second Viper and I've made well over 50 passes on a dragstrip between the two not to mention "exhibitions" on the street, so I'm no stranger to the T56.

your issue is not related- you are experiencing the inherent "dead spot" in the T-56 shift pattern. You can only find it when the car is moving, not when sitting still. This spot is right between the 3/5 gate, and when you hit it, you cant go into either gear, it keeps you in nuetral. The easiest way to prevent it is change the way you hold the shift knob. Make sure you dont "grab it", otherwise you tend to push it over too far. Try to push it straight forward, slight right without holding it very tightly.

 

[MoparMan]

your issue is not related- you are experiencing the inherent "dead spot" in the T-56 shift pattern. You can only find it when the car is moving, not when sitting still. This spot is right between the 3/5 gate, and when you hit it, you cant go into either gear, it keeps you in nuetral. The easiest way to prevent it is change the way you hold the shift knob. Make sure you dont "grab it", otherwise you tend to push it over too far. Try to push it straight forward, slight right without holding it very tightly.

Thanks for the tip. I've been backhanding the shift knob on the 2 to 3 upshift. On my GTS, I've got the Hurst short throw shifter and an MGW shift knob so I'm guessing that the issue isn't magnified nearly as much as it is on my stock SRT-10 Coupe.