Clutch won't engage at all. What broke?

I have driven Manual trans vehicles for the last 35 years and have never come across this. Started the truck, released clutch and it doesn't engage at all. You can leave it in gear, it won't stall or move at all. Idle's fine, clutch pedal feels normal. If you listen close you can hear a low rumble or growl. it's pretty subtle. it will just sit there and idle in gear, 1st or 2nd gear doesn't matter. Something had to break, I'm guessing.

Any ideas?

Thanks

Chris

 

IMO
If you have clutch pedal (doesn’t drop to floor)…..it’s not clutch MC

lemme ask you this
Prior to this issue, did you ever feel a surge in RPM’s when trying to accelerate?
Like Hwy speed, in 5th gear, stomped on go pedal and engine revvved up ?

 

Initial guess is throw out bearing(the humming noise)or clutch fork bent(not engaging clutch)
Internet guess mind you

 

Sounds like maybe a clutch disc/pressure plate failure. Throw out bearings whirl/rumble when they're bad, but you'd still be able to drive the vehicle around.

 

Surge in rpm's when trying to accelerate sounds like a slipping clutch and I haven't noticed that. I have a clutch pedal (it doesn't drop to the floor) I always thought if you pedal went to the floor and stayed there it was the slave cylinder. Pedal feels normal. Clutch has about 100k on it, it was replaced by the PO himself. The one thing I've noticed for a long time with this clutch is that when it's cold sometimes the first few shifts you might get a shudder as it engages. After the first few shifts though it's always been fine.

 

Yep MGM^^^

I RR-d a clutch one time
The disc was ‘OK’ as far as thickness but 2 of the springs incorporated into disc were cracked
Very possible

 

Definitely sounds mechanical (clutch disc/pressure plate related) vs a hydraulic issue with the slave or master cylinder.

What's weird is when the pressure plate lets go you normally get some feedback through the pedal. You mentioned the pedal engagement seems fine.

I'd still drop the trans and pull the clutch. Plan on replacing it along with the throw out bearing. I like to replace the slave and master at the same time.

 

This happened to my 2nd gen. It was a cracked clutch fork...
Pushed the clutch down to start the truck and that's when it broke....Pulled it back up....stalled...

Tried to push it back down..No dice...ALL MY WEIGHT...

Not advised either because I think this ended up prematurely rupturing/wearing out my clutch master cylinder.

 

I would just drop the transmission and not guess around here unless its pretty obvious

 

Sounds like the main spline shaft

 

could you visually see the fork from top of engine?
Or was crack found after tranny out?

 

You mean the output shaft of the transmission? Like maybe the pilot bearing is seized and won't allow the output shaft to rotate?

 

They had to drop the transmission and open her up...

Reasonable repair from a local shop at the time...
Parts were $615 Clutch kit full assembly, Slave, custom bent lines, they put in a new transmission mount as well...
Labor $510...

 

yes output shaft
I had an auto transmission break the spline. Shifted gears but no go...obviously.

 

If pilot bearing is seized it would stall id guess. But he said it doesnt stall

 

dang
Hoping OP could see w/out tear down

 

You have confirmed the clutch is actually moving the fork, correct? Look under truck, have someone work the clutch (engine off.)

 

Thanks for the ideas and input guys. Every bit helps. It's sitting about a half a block away on a city street. It doesn't seem like it's going anywhere without being towed. I have a garage behind my house but it's uphill from where this thing sits. No indication of a clutch issue when I parked it there a few days ago. I'll try and have someone work the clutch while i'm under the truck tomorrow or wednesday. I have not confirmed the clutch is moving the fork. I'll be very honest - although i've been driving with a clutch my entire driving life, I don't know much about how the parts work mechanically to do what they do. I have a feeling by the end of this I'll have a better idea.

 

Chris,
Parking on a city street points me in a different initial direction. Check to see that some A-hole thief did not steal your rear driveshaft while your Taco was parked up the street. If the DS is there, try moving your Taco in 4WD if you have not already done so.

 

Wanted to update this. I haven't had a chance to deal with this as I got a puppy on 5/9, but today I went out and put it in 4WD and the clutch engages and the truck will move.
So what's broke? I still don't know. I had the rear diff completely rebuilt from a reputable shop in NC that primarily rebuilds diffs. That was only about 15k ago.

thanks

chris