First of all........new to this site.....and really enjoy it. Now to the problem. I have a 1990 F250 4wd with a 7.3 diesel and 5 speed. The truck has 125k miles. Bought the truck and drove a week.......and the clutch started to chatter real bad in 1st or 2nd gear take off and reverse. No problem..........had the mechanic that works on my dumptrucks replace the clutch. He recommended putting a high dollar ceramic clutch in......to eliminate any future problems. I do pull a 8000 pound skid loader from time to time with this truck. OK.........fast forward....truck done and still chatters terrible. The clutch he took out.......looked to be in good shape .....Mechanic at a loss..........not too mention the $1000 it cost me. Motor mounts appear to be in good shape. Don't feel any movement in the shifters when I take off. Did not ask him about the trans mount. Where else can it be?

 

Well, its your flywheel buddy. The 7.3 5 speed combo has a dual plated flywheel. And the clutch shouldnt have any springs on it, but the flywheel does. If you beat on the truck, it shears the springs off and causes that chatter that you're hearing. I bet it chatters when you shut the truck off too.

 

GNR..........thanks for the reply.......The flywheel had already previously been updated to the style with out the springs.....my mechanic did have it resurfaced.....and the machine shop....said it looked good. No chatter after it shuts off........or after initial take off.

 

My best guess with that knowledge, is that it might still be your flywheel. If it gets resurfaced, they have to put a shim to keep the flywheel from moving back and forth. if there isnt a shim, then it will also chatter. The truck I have had the flywheel resurfaced before i bought it, and it did a similar thing because there was no shim. I'd check that out.

 

I appreciate the info.............I will pass this on to my mechanic. The previous owner.(who I totally trust) stated he never had any problems with the clutch. I own it a week and it starts to chatter. I am an owner operator of a dump truck co.....so I drive heavy trucks with clutches every day.............so I really dont think......the problem is due to my negligence.......????

 

Oh yes, everyone completely trusts the previous owner that just happened to forget to tell you all the problems before he sold you the truck. If you're used to driving heavy trucks, then I'm sure that the problem is the fault of who you bought it from. He probably wasn't bright enough or didn't care enough to take care of the problem. But I digress. I would just see about replacing the flywheel.

 

Some causes of chatter,
Oil or grease on clutch facings.
Warped clutch disc.
Warped pressure plate.
Sticking release levers.
Unequal adjustment of release levers.
Uneven pressure plate spring tension.
Loose engine mounts.
Loose splines on clutch hub.
Loose universal joints.
Loose bellhousing bolts.

 

I just had a similar problem last week my truck started to chatter taking off from a start. i just put the new clutch in this past spring when i rebuilt the motor. Now my truck has a 460 but it should still be the same tranny/clutch hydraulic system. last night i pulled my truck at the county fair, pull went fine i got unhooked from the sled and driving off the track i shifted into third it shifted really hard for some reason but then when i parked i depressed the clutch pedal and nothing happened and i almost hit another truck. anyways im really thinking the slave cylinder was my problem this past week maybe binding up or something i dunno but the master cylinder is full of fluid but the slave doesnt move...

 

Spoke to my mechanic this morning........he feels that the combination of 3.55 gear ratio.....and taller tires 265/16....are most of the problem........I disagree!

 

My mechanic...........going to tear back apart Tuesday...........Any other ideas on where to look........before he tears it down again?

 

Okay, heres my question to you, is it chattering right under your feet? See if you can pinpoint the noise. that little of a difference in tire size wouldnt cause a chattering. at worst it would stress the U-joints.

 

well i found what my problem was, i took the tranny out and found that my clutch disc kinda exploded i have no idea why or how it still moved but the problem why it wouldnt disengage was because there was so much of the disc fibers and whatnot packed into the pressure plate it couldnt move to disengage so it wasnt the slave cylinder afterall but gotta replace the clutch set

 

93, now that clutch was worked hard! Glad you found the problem.
duk, make sure that the friction disc you have is the one for a SMF and not one for the stock DMF.

 

the "birds nest" syndrome (seen in '93's pics) is most common from resting your foot on the pedal too hard when the clutch is supposed to be engaged.

to the OP: the "high dollar ceramic clutch" you put in chatters. all ceramic single disc's chatter, theres no way around it. i hate to say it, but the mechanic basically gave you bad advice from the start. . .if you dont want chatter, you cant go ceramic. organic/feramic materials are the only single discs that will have minimal chatter. . .since you've already dumped all that money and time into your setup, it might be best just to let it be and accept the chatter for what it is and keep the ceramic along with the chatter thats associated with high hp single disc ceramic clutches.

http://www.valairinc.com/performance/89-93.html

the lightest hp rating (looks liek 350) is what you want. as you can see, it's organic and its <300 bucks directly from the manufacturer (it can be bought for much less from a vendor or a site sponsor). . .i dunno what he got you to buy but thats a performance (better than stock) clutch for close to nothin. gotta steer clear from kevlar/ceramic. . .not only do they chatter, but theyre a waste of money. its way too much clutch for ole 7.3.

 

89F2urd...........maybe my choice of words (chatter was incorrect).......what happens when letting the clutch out in reverse or 1st or 2nd gear......is the truck shakes and shudders.....until it gets rolling. Then no other problems shifting between gears..... The previous clutch.....which appeared to be in good shape........did it way worse after driving down the road 50 miles or so. The problem happens only when trying to take off.