Clutch Chatter and Excessive Diff Slop

[SantaCruz510]

Hi all, I'm wondering if the amount of slop in the differential propeller shaft input is too much on my 510. 

 

https://i.imgur.com/aUJ3A5B.mp4

 

I have some clutch chatter that I also need to fix - I had replaced the clutch but the chatter remains. I had not resurfaced the flywheel, and maybe there is also grease  on the surface as per this thread: 

The clutch chatter is very audible when partially disengaging the clutch (partially pressing on the clutch pedal) and the engine speed is low - noticeable in any gear. Most of the noise seems to come from the propeller shaft rotational "bounce" due to the slop.

 

https://i.imgur.com/qx2g4Sc.mp4

 

So I wonder if I have 2 problems, the diff slop and the clutch chatter or if the only problem here is the chatter.

 

Thanks for the help.

 

 

 

 

[datzenmike]

I think if the clutch and PP were replaced there would at least be a change. Having said that, the flywheel should at least have the glaze broken with a sandpaper covered block of wood. If you  fingernail catches when rubbing across the flywheel surface, have it machined.

 

 

Better to eliminate everything else first...

 

 Most likely..

Check ALL 6 of the driveshaft U joints for looseness. Transmission in gear, lift one wheel at a time and have someone rock them back and forth while you inspect each U joint. Hold, if you feel any movement other that just turning, replace them. Transmission out of gear, each yoke the U joint seats into should not move at right angle to the axis of rotation. Grab the shaft on each side of the U joint and pull sideways forcefully. Don't worry, you could never exceed the torque they are designed to handle. Any movement other than rotation... replace it.  

 

Runner ups...

Lug bolts tight? you'd be surprised how often this happens.

 

Differential firmly bolted to sub frame? Mustache bar bolts tight and bushing in good shape?

 

Are the shock absorbers in good shape? no leaks? haven't gone soft? Bolts tight?

 

Any chance one of the coil springs is broken?

 

 

 

[SantaCruz510]

Hi Mike! RE flywheel: there was definitely no ridges, it was relatively smooth. Unfortunately I didn't take pictures nor remember if there was any glazing or hot spots.

 

I did replace all u-joints on the propeller shaft and output shafts and checked bearings and replaced bad ones on the rear passenger side. I did have one u-joint go in too easy into one of the "ears" of the propeller shaft, I'll double check if there is any slop.

 

Yup, lug bolts are def tight, which it would have been something as simple as this.

 

The diff had actually not been firmly bolted at one point, but thats been taken care off a few months back. You can see the gap there was before:

 

Good point on the shocks, I'll check them out now that the weather is getting better here in the bay area. The coil over springs are def still good.

 

I'll also try and open the diff while its still bolted to the car and see if I can measure the backlash, something similar to this video: 

 

It seems that the more the backlash, the worse the clutch chatter.

 

Thanks for the tips!

[datzenmike]

10 hours ago, SantaCruz510 said:

...

I did replace all u-joints on the propeller shaft and output shafts and checked bearings and replaced bad ones on the rear passenger side. I did have one u-joint go in too easy into one of the "ears" of the propeller shaft, I'll double check if there is any slop...

 

If the yoke that holds the U joint should be a press in fit. If loose the driveshaft will move around under load. The driveshaft is precision balanced and must spin on the center line. If ANY looseness it can only shift off it's center line position and will vibrate like hell or perhaps chatter.

 

Check also the rubber transmission mount and the rubber parts of the engine mounts.