I've had my 76 390 V8 2wd stakebody truck since manufacture. The 1st clutch held up well, but eventually needed replacing. This was many years ago. The replacement chattered badly when you started [no load] in 2nd. [You never start in 1st unless under a heavy load -it's a creeper gear.]
I have since put in 3 or so more clutches over the years, each time telling the next new mechanic - fix the chattering/jumping start in 2nd. Nobody could - I tried at least 3 different mechanics - large shop, small shop,truck expert, you name it.
So I still have to start the truck in 1st unless it's unloaded and pointed downhill.
If it's uphill or loaded, it bucks/chatters/jumps - not doable.
New heavy duty clutch,pressure plate, throw-out bearing. All done each time. You can see the scoring on the clutch when you pull it. But nobody knows why or how to fix it. Any ideas?

 

Thats tough to figure out for me ,I run a three finger & diaphram pressure plate in my 75 f250 with a 390,even the old high mileage units was fairly smooth with 2nd gear take off loaded heavy, is your linkage working smooth with out binding,do you have correct throughout bearing & fork.

 

If these are jobber clutches that could be the problem.

I have seen many that the fingers were way out of whack.


Get one from Ford.

 

I cannot remember if there was a Ford manufactured clutch ever put in.
You think that could make such a big difference?

 

I never had a Ford clutch,& had smoothe engagements.

 

your first post never mentioned machining or replacing the flywheel.

has that been done with any of the clutch jobs?

i had this happen once on a little car. worked OK if you walked it off the line at an idle, but with any throttle input it would chatter quite noticeably.

problems started with a failed throw-out bearing, so i had that fixed and had a new clutch and pressure plate installed and flywheel machined at that time. chatter was bad from that day on. a couple of months later i had the flywheel replaced with a new one. this helped but it still chattered. the guy who put in the new flywheel saw some debris in the bellhousing but didn't know what to think of it at the time. after i reported to him that the car still chattered, he began to suspect that there was something internal wrong with the trans.

never did find out. i just drove it that way. i put nearly another 100k miles on it before i stopped driving it, so whatever it was couldn't have been too serious.

can a comparison be made between a little car and a big truck? i don't know, but in principal, all clutches work in the same way.... so based on the problems i've had id suspect the flywheel or an internal problem in the trans.

but i'm far from being a transmission guy ... i just hang out here mostly to learn what i can.

good luck!

 

Some aftermarket suppliers try to cheap out.


I was in the business for many years and have seen good and bad.

Never had a bad one from Ford.

 

Thanks Mike - that is something I'll have to take a look at. I appreciate your input.