The Stovebolt Site Forums The Shop Area Engine Shop clutch chatter

'49 3/4 ton. Pulled the driveshaft and bell housing cover getting ready to r&r the clutch. Oil all over the oil pan, clutch fork, and throwout bearing but the plate and all other clutch parts look totally dry and clean. I understand that it is hard to tell without getting in further. Anyway, one of the transmssion mount bolts is totally lose, rattling around - almost fell off. I see some clean metal around the other transmission mount like the whole thing has been sliding around a little bit. Looks like maybe a 1/2 inch or so. So now I have already replaced the driveshaft carrier bearing and cushion thinking that was causing the chatter. Now I'm wondering do I fix up these mounts and put everything back together again and give it another try or go for a whole new clutch while I've got it up on jack stands even though the clutch looks good from here.

If the mounts are loose or worn out it could cause drive line problems. Personally I would do the mounts first before tackling the clutch. The shop manual makes reference to clutch problems being derived from bad mounts - both motor (excuse me - engine!) and transmission.

leon2982,

What a conundrum! Do ya feel lucky..huh, well do ya?

This is how I would approach this situation.

The drive shaft is already off. The gravel shield is off and several of the transmission bolts are almost off, so not much work left to pull the tranny and R&R the clutch.

The bad center bearing probably rattled the transmission bolts loose, and just because there isn't oil on the clutch doesn't mean it's OK.

Your are under the truck now. Finish the job and you wont' have to be under it again!

Guess wrong about the clutch and loose screws and you will have to be under it again!

You already know the correct answer, you just need someone to tell you that you already know it!

Stuart

Do it all now,Leon. End of problems!

I always have to look at it like "Do I have more time to put into it,or more money?"
If money's a little short but you have some free time,you might go with replacing the mounts and give it a try. while you have it that far apart,you might as well drop the clutch out and look at it.If it looks okay,clean it all up real well and throw it back together and see how it works. Of course,Seems like in my case I always try the free stuff first,and if that doesn't work I bite the bullet and pay less on the utilities and buy parts.
If money's not a problem,do as the guys say and go the new clutch,pilot bushing,flywheel re-surface,release bearing,and input shaft seal. Like they said-then you won't have to mess with it again.
Speed

It looks to me like the clutch components are all good. I need to jack up the motor and clean-up the transmission mounting area and take a picture to ask what I need. I'm not seeing on this truck what I see in any of my books. Can I jack up the motor by the bell housing or will that crack?

leon2982,

The bellhousing won't crack, but if you are going to remove it, you will have to support the engine at some other location.

If you lay a piece of 2X6 on top of a hydraulic jack, you can lift the engine from the pan. This works well, is plenty strong, and allows free access to the bellhousing and transmission area.

Lift only enough to clear the rear motor or tranny mounts.

It sounds like you are on the right path, but remember, the physical appearance of the clutch and pressure plate can be misleading. If they were cooked and consequently glazed, they might appear fine, but can still cause chatter.


Stuart

Alright. I'll buy a clutch kit anyway. I guess I'm getting old. Not willing to take a chance? I'll clean up the transmission mounts and take a picture. The bell housing is sitting on a cross member. There is one bolt on either end of the housing going down through the cross member. The passenger side still has some rubber on it but the bolt is rattling around; not even close to being tight. The driver side looks to be metal on metal. When I was pulling the transmission, the bell housing was moving back and forth sideways without much effort. The only mounts I've seen must be for another application, maybe 1/2 ton, because they have 2 holes. The one mount on this truck that still has some rubber on it is u-shaped.

Here is a picture of the bell housing jacked-up off the cross member.
bell_housing

The right side had this mount and a rattling bolt not even close to being tight and the left side had nothing except a tight bolt; no rubber at all. I'm thinking Patrick's might have a mount like this. Any other suggestions?
mount

Here is the left-side of the housing. It was just bolted to the cross member.
left

Here is the right-side. It had the rubber and metal u-shaped mount but the bolt was not close to being tight.
right

Here is the disc and plate I pulled out.
clutch

Here is a picture of the still-mounted flywheel. Does that look like a crack?
flywheel

The bell housing would move back and forth pretty easily when I was wiggling the transmission out.

leon2982,

I haven't seen rear motor mounts in quite awhile, but I am pretty sure yours are destroyed, if nothing else, by the oil.

A flywheel very rarely cracks. You can sometimes mistake heat checks for cracks...I guess they are shallow cracks.

Before you try specialty suppliers, try your local NAPA or auto parts store for mounts..they are probably common to many years!

The motor is supported on the front mount only, and you will get plenty of wiggly when attacking the back end.

Those are great pictures. To my poor eyes, I would say the clutch has been oil soaked, and then cooked. A total fix would include having the flywheel surfaced for some new "tooth" to go with the new clutch.

Would it be wise to see if you can find out where all that oil is coming from! Remember that the bolts holding the flywheel on actually go into a cavity inside the engine...full of motor oil, don't leave any out. Good luck!

Stuart

Found a broken spring on the clutch disc and the center of the disc has separated too. Not gonna work like that for sure. Will order a new kit tomorrow and look for motor mounts. Thanks lots to all who have helped with information.

broken spring

I've had two cases where I had clutch chatter & in one of them it had some center hub spring damage such as yours shows. In both of these cases of mine when I finally found & cured the problem, it was due to mis-alignment of the engine/trans. My most recent one was with a 292" 6-cyl. I swapped into my car. Used the same trans. I'd ran in the car for maybe 50K mi. with a 235, no problem. Long story short, a set of .016" offset block dowels to get it on center & a pair of .010 shims under the top trans. bolts to correct the angularity & its now a pleasure to drive again. Two clues I had-it had excessive pilot bushing wear & when shifting from nuetral to rev. it would try & grind the gears. No matter the disc was releasing OK, it would not 'coast down'. All this is fixed now. If you had these symptoms I would recommend getting a dial indicater & checking the alignment. Doug

desertdog: I have not heard of checking that alignment. What do I check?

Leon- wish I had a little more computor experience, I'd give you some links. All I can offer is go to google & search for 'bellhousing alignment'. You'll find some good reading there. If you go to www.chevytalk.org & do a subject search, its been well discussed there. Doug

That works for me. Thanks for the information.

Leon, did you change the u-joints when you did the center support and if so where did you get the joints from and would you have a part number and vendor???
Denny Graham
Sandwich, IL