clutch chatter question

[2tone4by]

just had a new clutch, pressure plate and throw out bearing installed in my  78 chevy 4x4 truck. The flywheel was also resurfaced. What would cause the clutch to chatter when taking off. This truck has a three speed tranny and I have had it many years and have had the clutch replace several times and it seems to always have this shaking and chatter when taking off. Any thoughts or ideas what might be the problem much appreciated.......

[bake74]

     Are the clutch linkages adjusted properly, and do you have all the springs associated with the linkages installed ?  See the service manual for your 78 in the link, found in the tech section.
    Is your Z-bar still still good, not loose and wobbly ?

[2tone4by]

all springs are new z bar is tight and lubed well and the clutch fork and ball is new. no matter how you take off it will shrudder the whole truck, both when in reverse or low. With transfer case in low, it seems to be smoother. All of the clutch linkage is tight or new.....just can't figure it out....all thoughts appreciated

[zieg85]

How is the transmission mounts?  Pilot bushing? 

[2tone4by]

new transmission mounts and pilot bushing as well

[zieg85]

Possible engine crank run-out (excessive)

[2tone4by]

I drove the truck today, and tried several stops and starts with the transfer case in low gear. It takes of every time smooth with no shimmy or shudder. same for using reverse....smooth. Could it be the gear setup in this truck is causing this. It came with the old L78x15 tire size. I am running a new set of p265x75x15 which is quite a bit taller. still scratching my head?

[bake74]

     Have you inspected the rest of your suspension ?  Maybe you think it is the clutch/transmission, but in reality the movement of take off is causing something else entirely to happen.

[bd]

How did the face of the flywheel appear before you had it surfaced?

[2tone4by]

everything else looks good....all u joints have been replaced....the flywheel has a few hotspots on it, but machinist said it would turn fine. It looked as new when I picked it up. I believe whatever is causing this has been going on for years.. I have had the truck since new, and have put at least 4-5 clutches in it through the years, and it always had this problem of shaking when taking off. I have run 32/11.50/15 tires for the last 25 years and  I kinda thought that was the cause, but apparently not the case.....I appreciate y'all's help, and keep the thoughts coming....thanks

[bd]

Starting off in 'low' requires less slipping of the clutch, resulting in quicker clutch engagement, hence decreased chatter. 

Visible 'hot spots' are evidence of a retempered facing, resulting in "hard spots" that create uneven friction for the disc - similar to hard spots in brake drums.  At this point your solution may require a flywheel change.  But, if you have an effectively high drive ratio (meaning that vehicle speed is relatively fast compared to engine RPM), because of gearing and tire size, it may not be long before the symptoms return.

The long-term solution might be to decrease tire size or regear.

[claude]

I had the same problem with a resurfaced flywheel and new clutch and pressure plate.  Replaced with new flywheel and problem solved.  Resurfaced flywheel had dark tempered (hardened) heat spots.  Machine shop that did the resurfacing should have known better and I learned a great lesson on trying to save $60.00.