Few months ago I had a new clutch installed at a family friend's shop. I got the car back and I noticed it was very jumpy, and every time I would take it out of gear it seemed like the tranny would shake or something. One of the techs said I just needed to break in the clutch, anyways this same problem has been happening ever since. I talked to my best friend's dad about it, and he asked me if I was having problems taking off, and having the car shake like crazy when I was actually shifting correctly. I of course said yes.

He then said they probably installed my clutch backwards? I was like WTF! is that even possible? So my question is, has this ever happened to anyone before or no? Maybe the tech that installed my clutch was drunk, but either way this Monday i'm taking the car in and making them check it.

 

Pass??? i dnot even know if this is poss?? anybody?

 

Not backwards. If it's even aligned SLIGHTLY off it will cause issues like this. This is why they have clutch alignment tools that come with them. I'd suggest taking it in and having it reinstalled as it will tear up the clutch and possibly more driving around like that...

 

my thoughts exactly.

 

The PRESSURE PLATE its self will only mount one way if they have all dowel pins in place.

The clutch alignment tool is there to keep the disc centered in the pressure plate when bolted onto the flywheel... Since the pressure plate will basicly be clamping the disc into place between the flywheel and pressure plate, it will not move around. The shaft from the trans will not go into the clutch disc properlly if it is not aligned. Once you press the clutch pedal and release the pressure plate the disc spins freely... that cant really be out of alignment once it is operating...

what kind of flywheel / clutch / more info?

 

Is your engine stock? I was having a similar problem, turned out that the turbo bypass valve was malfunctioning, nothing to do with the clutch.

 

Ok...then why when you have this happening and you disassemble the clutch components and put it all back together with the correct alignment does the problem go away?

I think the one crucial piece of information that is being overlooked is this:

When you align the clutch disc between the flywheel and pressure plate correctly, meaning centered, the input shaft of the gearbox is centered too. Where the possiblility of vibration comes from is the fact that the gearbox to engine alignment dowels are only approximate, as are the unthreaded holes in the bell housing that the bolts go through to hold the gearbox to the engine.

If everything is aligned correctly, the line from the front of the crank shaft all the way to the tip of the gearbox out put shaft is all one unbroken line. If the clutch disc isn't centered properly, then the gearbox is slightly offline.

To see this in action, on a very simple level, take 3 circular objects, CD's for example, and stack them together. Look at the pile. If you have them all lined up it looks like one thick CD. If they were spinning the stack would be balanced. If you slide the middle one out just a little and then spun the stack it would wobble, as some of the mass would be off center. Now, imagine the top and bottom CDs being the flywheel and pressure plate, and the middle being the clutch disc.

And yes, I have experienced this in the past, and a disassembly and re-assembly with propper alignment cured it.

Sorry to rant...and I guess I had better add FTW to this post so it is taken seriously.

 

you dont think it maybe something else wrong? once the input shaft is in the clutch disc if you can even get it there when not aligned, releasing the pressure plate, the disc / input shaft will center its self.. its free floating once the release bearing presses the pressure plate..

if the pressure plate its self is not aligned then i see vibration being caused from this...

 

Jason is 100% correct here. The alignment tool is included so that you can put the transmission back on the car Once you disengage the clutch for the first time, by depressing the clutch pedal, the disc floats and is always in alignment.

 

It is not free floating. It is riding on the splined input shaft of the gearbox. And if the clutch disc wasn't aligned to begin with, the gearbox is bolted into place slightly out of position. It is because of this that the clutch disc can't re-center its self.

 

You guys are making this much harder than it needs to be. The clutch is engaged to the splines on the input shaft. The tool is used just to allow the input shaft to slide onto the clutch. If the clutch is not centered, the input cannot be inserted through the clutch.

Once the trans is properly in place, alignment is not an issue at all.

 

Well, by your logic we all need to come up with another solution to the original problem presented in this thread, because it can't possibly be that the clutch disc is out of alignment with the pressure plate and flywheel.

 

So the input shaft on the transmission alignment is based on the alignment of the clutch disk... thats like saying a pole jammed into the ground changes alignment as you toss a ring over it...

the problem here could be a number of different things... I was just stating it could not be the alignment of the disc... we dont have much information here from the OP...

what clutch package was installed? was the stock flywheel re-used? if so how many miles? ive seen stock flywheels with 30K on them with completely worn having no tension left in the damper ... what that damper worn, that could make for a jolting every time the pressure plate is clamping down on the on the clutch disc...

 

Actually, the input shaft alignment is based on the disc placement.

On every input shaft that I have ever seen (and I have seen a few, I was pretty hard on clutches as a kid...) the first half inch or so was unsplined, as this was the bit that was recessed into the pilot hole in the very center of the flywheel. It's not a tight fit obviously as the whole point of a clutch is to mechanically disconnect the engine from the gearbox. So, we can count that as the first place we can be a little bit off center.

Next, we have on either the engine block or the front of the bell housing some alignment pins/dowels. These are also not a tight fit. Another place that can allow the alignment to be off a little.

Then, finally, we have the bolts that attach the bell housing to the engine. All the pairs I have ever worked with it was either a nut and bolt, or the block was threaded and the bolt was inserted from the gearbox side. The unthreaded holes are likely to be a little oversized due to variances in the manufacturing process, which allows the bell housing/engine block alignment to be adjustable for lack of a better term...

So, here we have 3 places that would allow the gearbox to be slightly missaligned with the engine, if the clutch disc was not properly centered.

I'm not saying that it couldn't be for another reason, just trying to show that it is possible for the alignment to be off based on the clutch disc not being quite right.

I've presented all the evidence I can think of, including the fact that I've experienced this before (not with a 350 though) and a disassembly and reassembly cured it.

I guess its time to just agree to disagree.

 

My guess, is that the OP has an aggressive or somewhat aggresive aftermarket clutch, and he is just experiencing the normal chatter/grab associated with these clutches.