Horrible noise while climbing up an icy hill with traction control?

2010 Toyota Corolla, 5spd. I was trying to get it up a snowy/icy hill this weekend and, although I succeeded, the car made a very scary noise that I couldn’t decipher. Here’s what happened:

When the traction control engages, it makes a sound like the ABS engaging. That wasn’t the noise that worried me. I was feathering the clutch and trying to massage the car up the slippery incline, and it started making a loud rhythmic banging noise. It sounded like what happens when you’re parked and you think the car’s off, but it’s not, and you take your foot off the clutch. The clutch engages and makes a bang, and the engine stalls. (Not that I’ve ever done that before.) That’s what it sounded like going up the hill, but about twice a second and very steady.

As soon as I heard it, I tried releasing the clutch pedal all the way, I tried feathering the clutch more, I modulated the throttle a bit, but honestly I was 3/4 of the way up the hill after 45 minutes of trying and I didn’t want to stop! So I bang-bang-banged twenty feet up the hill or so, then when I stopped at the top the car seemed fine. I’ve since driven it another 300 miles of city and highway and no issues whatsoever.

Now, I’ve driven stick for twenty years and dozens of cars and am very comfortable in my own skill. This clutch has always seemed a little screwy since we bought the car, but the dealer mechanic told me (when I mentioned it early on) that it’s normal. It’s hard to describe why I think it’s screwy but it doesn’t feel like any other clutch I’ve driven, new or old. Including, every once in a while, when I’m pulling away from a stop sign in normal (dry) conditions, the clutch will chatter a couple times as I engage it. It’s far from a consistent or reproducible problem, and I always wrote it off until this recent episode that sounded/felt similar but much much worse.

Any ideas? Could there be oil on the clutch plates? Could this have something to do with the traction control? Thanks in advance!

Traction control applies the brake on the wheel that is spinning to transfer power to the other front wheel. Not a big deal for a moment to get the vehicle moving but for 45 minutes that is hard on the brakes.

Next time try turning the traction control off.

Page 163;

If the vehicle gets stuck in fresh snow or mud, TRAC and VSC may
reduce power from the engine to the wheels. You may need to turn
the system off to enable you to rock the vehicle in order to free it.

True. I wasn’t riding the VSC the whole time; in fact I turned it off early on.

Did it continue to make the noise with the traction control/VSC off?

Yes. The VSC noise sounds just like the ABS. This was totally different.

Whatever is going on, I’d definitely stop slipping (feathering?) the clutch.

Perhaps it didn’t remain off, at a certain vehicle speed it will turn back on. Was the Trac light on the entire time or was it flashing?

Trac light flashing means it is active, not off.

Ehh, I wasn’t totally watching the VSC light the whole time. I’m not sure if it came back on automatically.

Any idea why a relatively new clutch should be slipping/chattering like that?

There are two lights, Trac and VSC off.

I think the noise was from the Traction control/front brakes. It is louder and more harsh than ABS actuation.

The manual transmission is plain awful in recent Toyota Camry/Corolla I think they gave up on any real design with them since masses no longer purchase. Never feather any clutch to lessen power as you are slipping it and wearing it much quicker.

My sheer guess it you did not disable the traction control system. Was a yellow light flickering like mad as this was happening(typically it will).

Sounds like classic clutch chatter to me. I’ve had a clutch chatter at odd times and never could figure out the combination of factors that caused it. I’d guess yours was temperature related since you warmed it up with the feathering.

A lot of traction control systems can’t be truly turned off–just reduced in sensitivity by the dashboard switch. The OP may have heard the system continuing to operate despite turning it “off.”

The only way I’ve found to stop clutch chatter (once it starts) is to stop and try again. Starting up an incline (more throttle and feathering) also seems to be a common factor.

Thanks for the ideas. It definitely wasn’t the vsc/trac I was hearing. Your thoughts about the clutch chatter (and the validation of my low opinion of this car’s tranny) make it all more clear.