Just replaced my clutch and the original motor mounts in my 1956 F100, very original 223 6 cylinder. Truck ran and shifted very smoothly prior to the clutch replacement. Now, getting up to speed in first or reverse causes tremendous vibrations or "chatter" of the truck. It's fine in 2nd and 3rd. Had new clutch looked at, all seems to be aligned. Could it be the new motor mounts? Need help!

Thanks,

John

 

Is it engine speed related or ground speed ? Is there any vibration when revving in neutral and is the noise the same with slight pressure on the clutch pedal ?

 

I am only familiar with 48-52 trucks but did you readjust your free play? I would think with a new clutch disc that would need to be adjusted.

JB

 

Is your new clutch a complete new clutch kit, or a rebuild of the old clutch? I had a bad experience with a new clutch kit for my 53 sedan, and two friends each had bad experiences with new clutch kits for their F-1 and F-2 respectively. I replaced my clutch with used Mercury parts (earlier year stuff, required a bit of machine work to put it all together), the F-1 friend replaced his clutch with an expensive diaphragm clutch (says it was worth it) and the F-2 friend is still suffering with a chattering clutch.

 

Just a thought, is the slipyoke on the driveshaft indexed correctly?

 

Thanks for the replies. There's no vibration from ground speed, it seems to be engine speed in first or reverse. I do not think it's the new engine mounts because if it was the mounts wouldn't the truck would vibrate in any gear/speed?

This was a new complete clutch kit from MAC's. No vibration in neutral, only when the clutch is depressed and shifting into first or reverse. No chatter first to second or second to third. Downshifting third to second is fine. Second to first, vibrations return. I've had two mechanics look at the truck. No answers.

 

1st and Reverse may not be syncromeshed by design and with a worn clutch, were able to slip into gear. With a new tight grabbing clutch, the lack of synchronization may be more pronounced. Double clutching and low RPMs can help.

 

Have you gone through all the mounting bolts and made sure everything was tightened down properly?

engine mounts, transmission to housing, housing to block, complete clutch assembly?

since you changed more than one thing, engine mounts and clutch, you need to isolate the issues. Once you have re-verified everything is tightened properly that you can reach without pulling the tranny and bellhousing then unfortunately you have to open it up and recheck all the mounting bolts in the clutch assembly.

Re-torque everything to value. As you check. Don’t assume because it feels tight it is fine.

 

What bmoran4 suggests sounds logical, especially since you say this only occurs when the clutch pedal is depressed during shifts involving first and reverse. It doesn't sound like a minor annoyance you can get used to or double clutch yourself around. At some point you are probably removing the transmission to inspect the pressure plate, disc and flywheel. Before I did that I think I would get some miles on this thing, even if that means mostly just cruising around in second and third and shifting between them often. The clutch disc probably isn't even broken in yet and you might be looking at a pile of parts that look just like they did when you installed them.

I've repaired a lot of clutches that were chattering, but they were usually worn and had visual hot spots on the pressure plate and/or flywheel, or the clutch was just too sticky for the driver's liking such as a competition clutch in a vehicle that saw street use. My definition of clutch chatter is the repetitive grab and release sensation you would feel only during the shift. Vibration after full engagement could come from many other sources. You seem to have indicated this probably is 100% during the shift when the clutch pedal is engaged. There is no issue at all when you are just driving in first gear? Slowly of course. I know first is basically a "granny gear" in most of these old three speeds. Almost forgot. The flywheel is reconditioned or new right?

 

My understanding is it's not while shifting but getting up to speed " as he worded it " . Does this truck have a two piece drive shaft that could have been installed out of phase or a bad hanger bearing ?

 

I will tell you my personal experience here….when we built our 52 F1 and got to the clutch, we were super excited and put it together too quick. I had a NOS pressure plate and used the disc and bearings from Ft Wayne. We didn’t adjust the pressure plate fingers and slid the release bearing on the hub without pressing it on. I think we probably should have adjusting the fingers checking for run out and pressed the release bearing onto the hub. Pretty sure our disc is hitting the flywheel uneven and causing chatter in first, it’s fine in 2nd/3rd. It’s manageable but something I want to go back and address.

JB

 

Post #6 describes it differently. I guess he'll have to clarify.

 

Didn't catch that . Yes he needs to clarify if this is with the pedal depressed or not . If it's just when slipping the clutch to get going it could just as easily be oil-grease on the disc or just needing a good burnoff . When I ran my garage grain truck clutches were a common repair . After many times of having customers come back 6 months later needing a release bearing because of new clutch wearing in and getting out of adjustment I developed a policy of putting it in a high gear and slipping it for 15 or 20 seconds before final adjustment .

 

Also, clutch chatter and general driveline vibrations are distinctly different symptoms to me. I'm truly not trying to be the word police but he is going to get dozens of suggestions that aren't helpful until we truly understand the problem.

 

Thanks so much for the help. Let me clarify. These seem to be driveline vibrations, not clutch chatter. Tremendous vibrations when the clutch is being let out while picking up speed in first or reverse. Second and Third are fine. This is the second clutch kit from MAC's. The first one had the same issues. Showed hot spots on the pressure plate. Are these just bad kits? Any better ones out there?