Sm465 clutch fork has massive amount of play

75k20

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i got a 75 k20 with a 350/465/205 set up

the clutch rattles like an AK while you’re driving down the road. anything from idle to cruising. i checked out the adjustment rod that goes into the clutch fork and i could literally pull it out of the socket with my hands.. i don’t know how it was driving

i tried adjusting the rod and it made the rattling even louder, i tried to find a middle ground while i drive around to work. i purchased new clutch pedal bushings from a local auto parts store but i’m not sure if the problem is in the transmission as well. is it normal to have a lot of play in the clutch fork if the linkage wasn’t holding it in place?
 

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Something is probably bent. Maybe the fork. Or maybe the throwout bearing is riding on the pressure plate or something like that. There is a lot of pressure on the spring on the pedal mechanism under the dash that seems to bend things over time. It makes adjusting the clutch kind of tricky. That is how my '84 is. The hydraulic on the '85 works much better, with less pressure.
 

75k20

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Something is probably bent. Maybe the fork. Or maybe the throwout bearing is riding on the pressure plate or something like that. There is a lot of pressure on the spring on the pedal mechanism under the dash that seems to bend things over time. It makes adjusting the clutch kind of tricky. That is how my '84 is. The hydraulic on the '85 works much better, with less pressure.

the rattle seems to come from the clutch rod going through the floor board. if i push the clutch pedal in slightly about an inch, the chatter goes away and so does the headache..

would replacing the pivot point bushings help this? or does there seem to be internal damage as well
 

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Sounds like a combination problem perhaps;
A) a pressure plate whose over-time-bent-fingers that's had better days, allowing too much clearance between the ends of the fingers and the face of your throw out bearing
B) and/or in conjunction with a bent throw out bearing fork.
Can you adjust out all the slop on the rod?
 

75k20

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Sounds like a combination problem perhaps;
A) a pressure plate whose over-time-bent-fingers that's had better days, allowing too much clearance between the ends of the fingers and the face of your throw out bearing
B) and/or in conjunction with a bent throw out bearing fork.
Can you adjust out all the slop on the rod?
yes by adjusting the rod i can no longer shake the clutch ford by hand, im thinking of pulling off the rubber boot and sticking a camera in to see what the mess is.

the transmission has paperwork for a rebuild transmission about a year ago, but that was before i owned it and a lot can happen in a year. who knows… it might be under a warranty
 

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If you tighten the slack to barely perceptible, does the clutch still work right? No slippage? That's what you are looking for, just tight enough to lose excess slack but not so preloaded to be always pushing on the clutch. I'm thinking you just need to adjust the slack out of the system.
Does this make sense
 

75k20

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If you tighten the slack to barely perceptible, does the clutch still work right? No slippage? That's what you are looking for, just tight enough to lose excess slack but not so preloaded to be always pushing on the clutch. I'm thinking you just need to adjust the slack out of the system.
Does this make sense
yeah that’s makes sense, and i’ve been driving the truck everyday to work, it’s my dd. i have the pedal setup to start to disengage the clutch about 1” of down travel in the pedal. this morning i pulled the carpet back and could stop the rattling noise by putting my finger between the rod and the floor, i’ll look and see if something is bent making it hit the floor
 

bucket

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Bad cab mounts can cause a misalignment too.
 

75k20

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Bad cab mounts can cause a misalignment too.
here’s what the cab mounts look like. i’m not sure why there’s metal cutouts stacked on top of the front cab mounts. any ideas?
 

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1979 c20

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Bad cab mounts can cause a misalignment too.
True. It can really mess up the cab/bed transition too. I have this problem.

I was under the impression that this just recently started, after having someone service the transfer case.

But at this stage of a squares life, it's time to consider changing the bushings out, using the reasoning behind replacing all the period rubber fuel lines. Those blocks on your front cab mounts looks like someone's idea of "fixed". The original mounts must be ate up some to stuff blocks of steel as shims.

On edit - it occurs to me that if the tone changes by pulling on the shifter slightly, it could be as simple as misalignment of the linkage, pulling on the fork when it shouldn't be exerting any pressure.
 
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bucket

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Yeah, those front cab mounts are probably not helping the clutch linkage.
 

75k20

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Yeah, those front cab mounts are probably not helping the clutch linkage.
i should be able to just get replacements and replace them one at a time right?
 

bucket

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i should be able to just get replacements and replace them one at a time right?
You will want to change all of them, but yeah. Replace them all on one side of the truck, then leave the bolts loose, jack up the other side of the cab and replace those mounts too. Then tighten them all up.

Of course it's not an urgent repair right now either. Just clearancing the clutch rod hole may be enough to fix what you were already trying to fix.
 

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