Clutch and input shaft (568)/aligning the clutch

[Dave]

My brother just got his '91 Spirit back, rebuilt the 568, but for some reason the guy installed a smaller input shaft. One that is from a 555/523. I guess the tooth count is 50 on the 555/523 and 30 on the 568. Don't really know why he did it, but now it brings out the concern if the Centerforce that was used normally in the 568 will bolt up fine to the smaller input shaft?

Also, does anyone have any tips on how to align the clutch?

[mcsvt]

My understanding is the 523 is large spline and I know 555 is small spline. So I am not sure how those input shafts could be the same. You should be able to test the clutch disc on the input shaft before installing the trans to make sure it will fit. To center the disc you should use one of the plastic centering tools, but a deep socket would also work.

As was suggested to me, if you make studs for the top two trans bolts the trans will slid onto them and be supported so that you can mate the block and trans much easier.

Have fun

[TurboGLH]

If it's got a small spline input shaft there's no way to use a disk for a large spline setup. As far as clutch alignment, do it right and get the proper tool, either a real clutch alignment tool, or the plastic ones that are splined for the disc. It doesn't matter which, but once you've tried to install a trans in a car when the disc isn't aligned you'll appreciate the small amount of time it takes to properly align one.

A side note on input shaft sizes

All 555's and 520's used a small spline shaft. But the shafts are not interchangeable, a 520 gearset must use a 520 input shaft and visa-versa.

90' 523's and 568's used a small spline shaft as well, and same as the 520/555 the proper one must be used with the matching gearset. With the 89 gearset's being the only exception you can't use a 520 inputshaft in a 523 or a 555 in a 568.

[Dave]

Ah, that was it, the 555 and 520 was what he said.

So we also have another Centerforce that came out of his '91 TBI Shadow that had a 555 in it. This will more than likely work, yah?

And for the clutch alignment tool, how do I go about using it? Never used one before.

[Frank]

Is it also correct that 91+ 523/568 went to a large spline?

[mcsvt]

The clutch alignment tool gets put into the disc and holds it centered while you tighten the PP. And just like Chris said, you don't want to try and put a trans on when the clutch isn't centered, ask me how I know

[supercrackerbox]

Easiest way to know, slide the disc onto the input shaft and see if it fits.

As far as getting and alignment tool, most good parts stores have them in the help section, a few bucks for the plastic one. In a pinch, I once used the handle of a 3/8" drive Snap-On wrench with a bit of electrical tape around it, worked pretty decent. Basically, you want to hold the assembly up against the flywheel, get your mounting bolts just started, and use the alignment tool to center the disc in the pressure plate. The tool will seat in the hole in the end of the crank when it's done properly. **Make sure you have the correct side of the disc up against the flywheel, all the ones I've seen have been marked. Then just hold it steady while you tighten the pressure plate bolts in a criss-cross pattern. I believe the torque spec is 21lb.ft., someone correct me if I'm wrong. Also, the factory bolts came with blue locktite on them, I do likewise.

[supercrackerbox]

The clutch alignment tool gets put into the disc and holds it centered while you tighten the PP. And just like Chris said, you don't want to try and put a trans on when the clutch isn't centered, ask me how I know

Also, don't hold the trans up by the clutch lever while trying to slide it on, you won't get very far! Ask me how I know.

[TurboGLH]

Is it also correct that 91+ 523/568 went to a large spline?

That's right, somehow I left that part out when I posted.

The clutch alignment tool gets put into the disc and holds it centered while you tighten the PP. And just like Chris said, you don't want to try and put a trans on when the clutch isn't centered, ask me how I know

It's a painfull learning experience the first time you do it, but it never happens again. I don't think I've ever swore at anything else as much as I swore at the car that night.

[tryingbe]

I never used an alignment tool.

I just use my rachet and center the clutch. Works fine every time.

Definately use thread lock on those flywheel bolts and pressure plate bolts. I was in junkyard pulling an A555 and notice that one of the pressure plate bolts have come loose and resting on the tranny input shaft, the other bolts have started to come loose but not out all the way yet.