1995 Sierra C1500 Clutch/Transmission problems

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Klassickarguy

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200K Mileage SWB 2 wheel drive, 305ci. 5 speed.
The other day driving back from Jacksonville, truck made a sound like a tire blowout. Pulled over, tires all good, no fluid or parts on the ground. Tried to release clutch, truck stalls. Try to roll truck in neutral, wont move. Emergency brake not engaged. Have it wowed home, pull rear wheels and drums, no issues. Disconnect driveshaft, no issue in rear end. Next step: Trans in neutral - driveshaft wont turn. Depress clutch to floor, driveshaft turns (not freely but with some resistance). Reconnect driveshaft, start truck with rear wheels off ground, put truck in gear, release clutch, truck stalls. Restart truck, put trans in neutral, release clutch, rear wheels are spinning.

Try to see what's happening with slave cylinder, but its all internal in the bellhousing.

Help!
Could this be a slave cylinder issue, or something inside the clutch?
 

Schurkey

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Try to roll truck in neutral, wont move.

Trans in neutral - driveshaft wont turn. Depress clutch to floor, driveshaft turns (not freely but with some resistance). Reconnect driveshaft, start truck with rear wheels off ground, put truck in gear, release clutch, truck stalls. Restart truck, put trans in neutral, release clutch, rear wheels are spinning.

Try to see what's happening with slave cylinder, but its all internal in the bellhousing.

Could this be a slave cylinder issue, or something inside the clutch?
I wouldn't expect hydraulic issues. If the trans is in neutral and the truck won't roll...I'm thinking there's internal trans problems. You have a functioning clutch since the truck doesn't stall with the pedal pushed, but does if you engage the clutch.
 

Erik the Awful

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I'd guess a broken clutch fork keeping it in one gear all the time. If you put it in neutral and depress the clutch, you have resistance because it's turning the clutch plate. If you put it in gear, it's trying to be in two gears at the same time and locks up.
 

Klassickarguy

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I wouldn't expect hydraulic issues. If the trans is in neutral and the truck won't roll...I'm thinking there's internal trans problems. You have a functioning clutch since the truck doesn't stall with the pedal pushed, but does if you engage the clutch.
Here is the strange thing : When the rear end is up on jackstands and trans is in nuetral, when the clutch is released, the truck does not stall and the rear wheels spin. (Like its in gear)
 

Klassickarguy

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I'd guess a broken clutch fork keeping it in one gear all the time. If you put it in neutral and depress the clutch, you have resistance because it's turning the clutch plate. If you put it in gear, it's trying to be in two gears at the same time and locks up.

Im guessing I have to pull the trans to change the fork?
 

Erik the Awful

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Here is the strange thing : When the rear end is up on jackstands and trans is in nuetral, when the clutch is released, the truck does not stall and the rear wheels spin. (Like its in gear)
Yup.

Im guessing I have to pull the trans to change the fork?
Yup. Sorry to be the bearer of bad news.
 

Schurkey

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I'd guess a broken clutch fork keeping it in one gear all the time..
Clutch fork? Do you mean shift fork?

I don't think this is a clutch problem, since there's a difference between clutch pedal "up" (can't manually turn driveshaft) and clutch pedal "down" (can manually turn driveshaft.)

But it could easily be a shift-fork problem, where it's stuck in a gear when the shift lever is in "neutral". Stir the shift lever, you maybe get two gears at once (locked-up) or put it in neutral, and it's only in one gear, so the wheels spin.

But...until there's further inspection and maybe some disassembly, I suppose it could be all sorts of failures.
 

Klassickarguy

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Clutch fork? Do you mean shift fork?

I don't think this is a clutch problem, since there's a difference between clutch pedal "up" (can't manually turn driveshaft) and clutch pedal "down" (can manually turn driveshaft.)

But it could easily be a shift-fork problem, where it's stuck in a gear when the shift lever is in "neutral". Stir the shift lever, you maybe get two gears at once (locked-up) or put it in neutral, and it's only in one gear, so the wheels spin.

But...until there's further inspection and maybe some disassembly, I suppose it could be all sorts of failures.

Just wondering why a shift fork (internal to transmission) would just do that while driving down an interstate in 5th gear about 75 mph? Wondering if a synchro or bearing locked up internally? Guess Ill just pull it down and see what the issue is.. as you can tell im trying to avoid it..lol
 
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