Clutch cha-cha-cha-chatter

[F350camper]

I’ve noticed in the hot weather my clutch has significant ‘chatter’ when I leave the stop lights. It definitely gets worse with heat. This is with an empty truck also.
60° and below no chatter
70° Notice slight chatter on some starts
80° all starts have light chatter
90° + bad clutch chatter, worried that it could actually damage the ZF or bell housing

Where should I start looking guys?
Bell housing bolts?
Motor mounts?
Other ideas?

 

[Dsl_Dog_Treat]

Rob,
Stop dancing to the Cha-Cha. Sorry couldn't resist.
Sounds like you might be getting some scoring on the flywheel.
When was the last time it was changed/resurfaced?
Could be getting some hard spots on the surface giving up to loss of grip.
OR could just be the pressure plate getting weak.

My 88 V-8 Ranger ga$$er would do that if I had been burning the BFG's hard for some time riding the clutch to get the rears smoking enuff to lock the front brakes.

Just a thought from here to there.

Ron

 

[F350camper]

It's a new LUK kit. Prolly has 20k on it. Man that would suck if the pressure plate is toast already.

 

[Agnem]

I wonder if you got it contaminated with something that gets more viscous as the temperature rises. Perhaps you can try holding the clutch in with the engine off, and shooting some brake clean in there on both sides of the disk.

 

[Pacific]

I have had a Luk clutch in my truck for just over 2 years now and no problems with it. It does chatter a little in reverse but it holds great its never slipped once.

I never had a clutch chatter from the ambient temperature outside I can't see how that would make a difference because the spinning flywheel is always cooling itself.

The only thing I can think of is maybe your brake fluid in the clutch master cylinder is boiling from the heat it would really have to be loaded full of water for that to happen.

Have you pulled the inspection cover off and have a look inside and see if there is excessive dust around the flywheel from the disk wearing fast ?

Are you the only one that drives the truck ?

Hows the transmission and motor mounts ?

 

[F350camper]

I spose some brake cleaner couldn't hurt. I may give that a try.

It's a real irritating problem the way it comes and goes. And I agree that its strange that it seems to be tied to the outside temp. I'm not sure what shape the tranny / motor mounts are in. They are prolly original. Is there a way to test these besides visual inspection?

 

[F350camper]

Have you pulled the inspection cover off and have a look inside and see if there is excessive dust around the flywheel from the disk wearing fast

not yet, just gathering ideas at this point

Are you the only one that drives the truck ??

yep, just me.

 

[Pacific]

The only way to check mounts is take a bar of some sort and pry against the transmission to see if the rubber has separated from the steel backing. If they are the original mounts I would replace them they are cheap because rubber does fatigue after awhile.

 

[F350camper]

Well now that its happening more often, and I'm paying more attention. I'm really starting to suspect those tranny mounts. I'll have to give them a look this weekend. We are back in the 60°s again, so it's smooth as silk again.

 

[LDW]

I put in a new 12 inch LUK clutch two years ago and it will chatter when you start from a stop. It never fails to grab and is smooth when shifting through the gears. If the truck is empty, it will jump a lot, but the heavier the load I put in the truck the smoother it gets. If I am pulling the camper it is very smooth from a standing start. I understand the big rigs clutches are the same. Run them empty and they will jump, but put 80,000 lbs behind them and they are smooth.

 

[Caver Dave]

Well now that its happening more often, and I'm paying more attention. I'm really starting to suspect those tranny mounts. I'll have to give them a look this weekend. We are back in the 60°s again, so it's smooth as silk again.

Need to check my tranny mount also! When I went to p/u my trailer from storage this weekend, I started noticing a dull "thud"... somewhere between releasing the pedal and starting to torque. Seems to be centered under the cab, like the transfer is rotating from the torque and making a thunk when it hits the lowerside of the cab.

I was advised to use a prybar to work everything around good... they're too big to move by hand like my TH400! Was also told to hold the brakes, & release the clutch in 1st...if the motor mounts are gone, it would obvious as the block will pitch. Not sure how much movement the mounts are supposed to allow, but I'm guessing not as much as typical gasser?

 

[F350camper]

This problem is solved. I replaced the tranny mount. On the old one the rubber was all cracked and allowed a whole lot of movement. And I assume it was even worse when it was hot out, giving me the strange tied to weather symptoms.