The Day Started Great then Went Down-Hill Fast

[HIZNHRZ]

Beautiful morning. On the way home from Cars-n-Coffee there’s a light that directs traffic onto an acceleration lane of a local highway. I make a slow left turn, hit the acceleration lane and incrementally (to avoid wheel spin) stand on it in first gear. I start my 1-2 shift at the precise time my shift light comes on. The car won’t go into second.

I let off the throttle, drift off to the side of the highway. It won’t go into 3rd or 4th. I come to a stop and try 1st. No luck there either. After trying each gear several times I’m able to force it into 2nd. When I let the clutch out it chatters and bangs like something’s broken off and is banging around in the clutch housing. No clutch plate burning smell but it smells like a piece of metal lodged next to a fast moving part getting hot and burnished. Once it’s in 2nd gear and the clutch is out, it runs fine, almost normal. I decide to try and drive it off the highway. It still will not go into any other gear.

I drive it slowly in 2nd gear and make it home. No sounds, no smells, doesn’t overheat, etc. I pull it into the garage and let it sit and cool down. Four hours later, I get in the car and depress the clutch. The clutch feels funny but it moves through its normal range of motion. With the clutch depressed, the car now will shift in every gear. I start it. Sounds like I suddenly have a vacuum leak but idles fine (no backfire). I can let the clutch out while in gear (in the garage) and rock the car. The clutch chatters but the car moves without any banging metal sounds. I back the rear wheels out of the garage. The rear wheels are now sitting lower than the front end. I put the car in 1st and let the clutch out (under load). The car moves but the burnishing smell returns and is prevalent; the clutch chatters and bangs.

I'm no expert but I have my own thoughts as to what happened. I’d be real interested in other opinions.

BTW, I was planning to take a road trip to Marc’s next month for a little maintenance and some mods. Looks like I’ll be renting a trailer and driving to Illinois with the ZR-1 and getting some repairs.

[Jagdpanzer]

Bummer Scott
Appears the clutch is not releasing like it should.
Could be clutch disc failure

[scottfab]

Sorry to hear. Sounds like maybe the fork let loose.
They have been known to bend and crack.

[QB93Z]

I agree with the above. It could be a clutch disc or a fork/throwout bearing problem.

Scott, I am planning a Westminster Maintenance Day on Sep 29th. I am busy every weekend until then. If you want to come up on the 29th, we can drop the transmission and see what's up.

Jim

[Moonlk]

Sounds a lot like what happened to my daughters VW Beetle this spring. Turned out to be clutch disc grenaded. Clutch fibers everywhere. 250000 miles on the original clutch.

[rkreigh]

my bet is clutch fork

I had a pressure plate lock up on my first drm 90 Zr1. that was interesting couldn't push down on the clutch pedal at all. pressure plate just froze and wouldn't budge (didn't know they could do that)

does the clutch pedal have full travel? hearing any noises when you push down on the clutch.

throw out bearing might have failed too but obviously the clutch isn't releasing

at least you made it home and the Z didn't strand you.

sorry to hear about the problem. time for a wazoo day.

[Schrade]

I have a 32k clutch fork, if you're in need. PM @ me here........

[HIZNHRZ]

Bummer Scott
Appears the clutch is not releasing like it should.
Could be clutch disc failure

Phil, if it were a disc failure, wouldn't it smell like a typical overheated clutch? This smell was more like when sharpening a knife blade on a grinding wheel.

Sorry to hear. Sounds like maybe the fork let loose.
They have been known to bend and crack.

Scott, that was one of my thoughts when I was on the highway and could not get it into gear. When I let is sit and cool, with the engine off and the clutch pedal depressed, it goes into all gears easily.

I agree with the above. It could be a clutch disc or a fork/throwout bearing problem.

Scott, I am planning a Westminster Maintenance Day on Sep 29th. I am busy every weekend until then. If you want to come up on the 29th, we can drop the transmission and see what's up.

Jim, appreciate the offer - very much! When I let everything cool off, I started the car, put it into gear and was able to move the car. When I backed the rear wheel just out of the garage, the load created trying to pull the car back in (slight uphill) was more than it could handle. It sounded bad. At this point, there is no way I could drive it Westminster.

my bet is clutch fork

...does the clutch pedal have full travel? hearing any noises when you push down on the clutch.

throw out bearing might have failed too but obviously the clutch isn't releasing

at least you made it home and the Z didn't strand you.


I can't rule out the throwout bearing but...full clutch pedal range of motion, car goes into all gears.

When the car initially would not go into any gear, the sound was like something broke and was banging/rattling around in the clutch housing. Then the banging/rattling stopped and the "blade sharpening" smell started.

Does a new pressure plate ever "blow"? What else could have "broken" and still have a full clutch pedel range of motion, be able to move the shifter easily into every gear, and not smell like an overheated or slipping clutch?

[HIZNHRZ]

You guys are great. I appreciate the thoughts. Me "pushing back" is not meant to disagree, it's more me wondering if I clearly "provided you with all the facts" as I remember them.

To prove a point to myself, I'm going to block the front of a rear tire and put the car into gear. What I'm expecting is to hear nothing unusual at idle with the clutch out. To hear something a little strange (but not bad) when I depress the clutch. To be able to easily put the car into gear but for it to sound like it's going to come apart as I slowly let the clutch out and the car tries to pull itself over the blocked wheel. I'll let you know how it goes...

[scottfab]

....snip...

Scott, that was one of my thoughts when I was on the highway and could not get it into gear. When I let is sit and cool, with the engine off and the clutch pedal depressed, it goes into all gears easily.

I have to tell you that 4mo after I got my car this exact same
scenario happened to me in Seattle when I was doing a lot of stop
and go in city traffic. NO shift was possible for about 15min while I sat. I kept trying to depress the peddle every so often until it popped loose. When I finally got around to rebuilding myZF6 the next year I found the fork was bent. No doubt from me pressing on it when it. My theory is that the clutch plate temporarily seized to the pressure plate. I replaced the clutch plate and roughed up the pressure plate
surface before reassembly and no issue since.



...snip....

When the car initially would not go into any gear, the sound was like something broke and was banging/rattling around in the clutch housing. Then the banging/rattling stopped and the "blade sharpening" smell started.

Does a new pressure plate ever "blow"? What else could have "broken" and still have a full clutch pedal range of motion, be able to move the shifter easily into every gear, and not smell like an overheated or slipping clutch?

I sure wouldn't drive it until I found out more. Remove the inspection
plate and see whaz-up.

[HIZNHRZ]

Scott, very much appreciate the input. At a minimum, I'm expecting to find a clutch disk facing that has failed. Sounds like I need to carefully examine the clutch fork.

I have only a couple of things left that I would like to do to my ZR-1. One was to send my transmission to Bill Boudraeu for his ZF B&B work. Looks like now would be a good time to move this project to the top of the queue.

[SteelBlueZR1]

Don't forget to have Bill install his short shifter when he does his ZF magic. Good luck with your clutch. At least this did not happen far from home. If you or anyone you know has Premium AAA, maybe you can have it towed to Westminster for the next WAZOO work day and buy a flywheel and clutch in advance?