My truck, 69 F250 2wd 4spd 360, bucks or shakes when I start out from a roll (second gear) Feels a lot like the pressure plate and the clutch don't match up, except both have been in the truck for quite some time without being touched. Is the clutch going? It holds fine all the time, just acts funny when I take off.
Thanks
AW

 

What you are describing sounds like clutch chatter. It can develop under normal driving conditions but can be a direct result of starting out in second gear (really not a good habit). What causes the "buck" is uneven wear on your flywheel. The only way to cure it is to have your flywheel resurfaced. Of course, if your going to do that, you might as well do a complete clutch job.

Joe

 

Well ummm, aren't you supposed to start an NP435 in second gear?
AW

 

Hi Aaron, how's your rear main seal? Does it leak much, maybe you're throwing oil up there. That could cause it to chatter.

Barry

 

i rebuilt my 67 and i was noticing a good amount of bucking every time i took off, when i pulled the clutch, first off, the pressure plate had a few bent out teeth... a good cause for bucking.. also, the moron that had the truck before me put a stell clutch pad in, so my flywheel and pressure plate each had a 1/4 inch groove in them the size of the clutch pad.

 

The rear main seal may be the cause. Guess I really should take it apart and see. Thanks for the wiring diagrams Barry, I got everything fixed up last night.
AW

 

Aaron, unless it is real bad I wouldn't worry about it. My 72 three speed does it too. When I have to but in a new clutch I am going to use a pressure plate from a 80 model ford truck. The 72 plate only has three forks for the throw out bearing to come in contact with and the 80 plate has little ones all around it. I think it is a direct bolt in but I'm not sure. All I know is my 81 with the NP435 didn't buck at all and I think that is why, because it had a more uniform pressure on the clutch. And yes, w/o a load you start a NP435 in 2nd to avoid putting your head in the back window...lol.

Jeremy

 

Well ummm, AW, why do you think they call it second gear and not first?

 

Jds...have you ever driven a truck with an NP435? First gear is for starting with heavy loads, its like a 6.76:1 (or so) gear and with a 4:11 rear end, its worth about 7 miles an hour, or maybe half way through an intersection. So unless I have half a ton behind my truck, I don't touch first gear.
AW

 

Ah come on Aaron, first gear is only 6.69:1, and spur cut, no synchro.

Hey, glad to hear those wiring diagrams helped. Now I have to hide everything due to the new guidelines.

Barry

 

Yes, AW, I sure have- call me practical, but I wouldn't use one to putt around town. Strictly a work horse as far as I'm concerned.

Never the less, you posted a problem, and I posted a response- no need to get your shorts bunched up about it. If you don't want us to offer any help, don't ask for it.

Hope you find what is causing your problem.

Joe

 

JDS

As an objective party here I thought I might try and help with the lil showdown. I think you are being a little rude, not him. He is right to start in second gear and practicality has nothing to do with what he chooses to drive. Most of these old trucks might not be practical. But if you want practical go get a lil compact car or something. I took his question about starting off in second as being just a simple question. If you took it as more maybe you were looking for something more. "ummmm" does not equal to insulting when you can't hear tone of voice.

I don't know anyone who drives one and doesn't take off in second, unless they're pulling a significant load. Sure they call it first, so what? If you think you have to start off in first in these trucks any and every time, then you're in the minority.

Not trying to start a fight here, just saying, maybe you took things wrong and should take a deep breath and re-evaluate. Just a suggestion.

-j.banks-

 

Maybe your right, j.banks- my intentions were not to be rude. As it is impossible to know AW's demeanor by his typestyle, it is also impossible for you to know mine. I was just stating that if I owned a truck and the first gear was too low to utilize when not loaded, that would not be my truck of choice for day to day driving- That's my preference. I wasn't trying to tell AW what to drive.

I drove a F500 with a utility bed and service crane for a couple of years. Even with 1500lbs of tools, it wasn't enough to load it down, in my opinion. But that didn't encourage me to take off in second gear. If everyone in the world took off in second gear and I was the only schmuck that didn't, I would still respectfully disagree with your opinion- that is just because of what I know (not trying to convert anyone, either).

At any rate- AW- I still hope you find a solution.

Life is too short folks-

Joe

 

...I drove a F500 with a utility bed and service crane for a couple of years. Even with 1500lbs of tools, it wasn't enough to load it down, in my opinion. But that didn't encourage me to take off in second gear. If everyone in the world took off in second gear and I was the only schmuck that didn't, I would still respectfully disagree with your opinion- that is just because of what I know (not trying to convert anyone, either)...

Jds..what do you know? Im not trying to be a smartass, but why do you start in first? Maybe there is something to be gained?
Thanks
AW

 

my 1st gear just got broken in after 189 000 miles of driving
it's used so little it gets me halfway across the street before
i shift and if I give it gas it sqeeks the rubber, first is
good for snag cruising when i cut fire wood,even with green
wood stacked to the limit 1st isn't required, except on steep
grades just to be easier on the clutch,the through out bearing
can also cause chatter when the clutch disengages.. I believe.


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