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John the Builder
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Failed clutch-fork arm pivot?
 

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John the Builder
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16,993 Posts
Yup, and it took the release fork and throwout bearing with it.
Crazy, ain't it? Had a F150 6-banger decades ago snap the pivot ball. Simpliest part on the damnbed truck, and bam!

I was luckier - only had to replace the ball.
 

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DPDT, Momentarily on
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718 Posts
Discussion Starter · #6 ·
you don't ride the pedal do you ??

sometime that happens without even knowing it..
Nope, and never have. When my grandfather and dad were teaching me to drive the ag equipment at 7 years old they made it plain I'd get my butt kicked if I ruined the clutch on any of the farm vehicles by riding the pedal. As much as a ***** as this is it's way easier than splitting a tractor. Foot stays the eff away from the pedal except when needed.:thumbsup:

Regarding this truck (93 GMC K3500) after 280k miles it has a right to get a little worn out. Come to find out GMT 400 series (88-98 GM trucks) are notorious for the ball pivot wearing out and causing other troubles.

I've had it about 5 months and it's been trouble from the get go. 3 clutch master cylinders and one slave in that time. This time the throwout bearing let go, so time to fix it right.
 

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DPDT, Momentarily on
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718 Posts
Discussion Starter · #7 ·
Crazy, ain't it? Had a F150 6-banger decades ago snap the pivot ball. Simpliest part on the damnbed truck, and bam!

I was luckier - only had to replace the ball.
Well if I'd got off my azz and done it sooner I may have gotten away with that, too. Live and learn.
 

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I'm The BOSS
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1,904 Posts
I wonder if the slave cylinder was sticking then,
I've seen that many times, bearing burns out and ruins the fork.
your pushing harder, but can't tell because of the hydraulic assist.
fork breaks or you punch a hole at pivot point.
 

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Administrator
Maker of Fine Sawdust
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51,898 Posts
My transmission in my 07 2500HD was slipping when it shifted from 2nd to 3rd. Like you were slow to engage the clutch on a manual and the engine would rev a bit and then slow as the clutch fully engaged.

It was a 79 cent O-ring. Glad it was a warranty repair.
 

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DPDT, Momentarily on
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718 Posts
Discussion Starter · #10 ·
I wonder if the slave cylinder was sticking then,
I've seen that many times, bearing burns out and ruins the fork.
your pushing harder, but can't tell because of the hydraulic assist.
fork breaks or you punch a hole at pivot point.
I've seen what you're speaking of on other vehicles in the past, but in this case it really was just the fallout from the pivot ball being worn out, not the slave cylinder sticking. This causes the required working pressure to operate the release fork to climb a lot, hence the next weak link goes bad. The bearing only went bad Friday afternoon, no noise or trouble at all prior to that. The fork had close to 1/16" wore into it at the pivot seat, and the ball had what looks like more than 1/8" wore off the end, as well as the retaining stud broke off. On top of that the way it wore caused it to have severe flatting going on, so that effectively moved the pivot point to the edge of the ball instead of rolling over the center. I'm certain given another 280k miles it would have punched through the release fork. But odds are that it wouldn't make it anywhere near that far anyway.

It's getting down to the short hairs now. Transmission/x-case are back in and I just have to finish up some odds and ends in the morning. Pedal feels way better than it did a couple of days ago.
 

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DPDT, Momentarily on
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718 Posts
Discussion Starter · #11 ·
My transmission in my 07 2500HD was slipping when it shifted from 2nd to 3rd. Like you were slow to engage the clutch on a manual and the engine would rev a bit and then slow as the clutch fully engaged.

It was a 79 cent O-ring. Glad it was a warranty repair.
How's that saying go?

For want of a nail a kingdom was lost.
 

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John the Builder
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16,993 Posts
How's that saying go?

For want of a nail a kingdom was lost.
Exactly. Still have to disembowel the rig all the way back to the flywheel. PITA!!!
 

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Nope, and never have. When my grandfather and dad were teaching me to drive the ag equipment at 7 years old they made it plain I'd get my butt kicked if I ruined the clutch on any of the farm vehicles by riding the pedal. As much as a ***** as this is it's way easier than splitting a tractor. Foot stays the eff away from the pedal except when needed.:thumbsup:

Regarding this truck (93 GMC K3500) after 280k miles it has a right to get a little worn out. Come to find out GMT 400 series (88-98 GM trucks) are notorious for the ball pivot wearing out and causing other troubles.

I've had it about 5 months and it's been trouble from the get go. 3 clutch master cylinders and one slave in that time. This time the throwout bearing let go, so time to fix it right.
Isnt that the nv4500 trans? I had the same thing- got harder and harder to get out of gear- I don't know if you have had the truck long, but usually its because when they do a clutch job, some people don't change the throw out bearing- and it wears out so badly, and destroys the clutch. The parts are cheap, but people often times don't replace it when their in there.
 

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DPDT, Momentarily on
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718 Posts
Discussion Starter · #14 ·
Isnt that the nv4500 trans? I had the same thing- got harder and harder to get out of gear- I don't know if you have had the truck long, but usually its because when they do a clutch job, some people don't change the throw out bearing- and it wears out so badly, and destroys the clutch. The parts are cheap, but people often times don't replace it when their in there.

Not a NV4500, a NP465 from an older truck. Been keeping an eye out for a 4500 just haven't found one yet.
 
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