Clutch Shudder

So I’m not sure “shudder” is the right word, but it’s a very inconsistent grabbing that causes severe vibration. This happens occasionally on the first few starts of the day and then goes away.

What does this mean… Worn out friction disc? Glazed surface? Contaminated surface? Could it simply be condensation?

What can I do about it?

50k miles, some towing, and I’m not going to pretend that I’ve been good to this truck, although I don’t think I’ve been THAAAT bad. For reference I replaced tires at 40k and brakes are on track to make it to 80-90k

 

Hard to say without driving the truck and feeling its behavior. Could just be a cold transmission, could be a warped flywheel. I'd probably start with fresh fluid and see how it reacts to that.

 

I had a first gen tacoma that did the same after sitting. I lived with it for a year or so and then finally replaced it. There was a lot of friction material left, so must have been glazed or degraded. Was never an issue after replacement.

 

Probably some hot spots on the flywheel and things are just worn. The only solution is to put a clutch in it and either machine/replace the flywheel. My truck does exactly the same thing, and I've seen it hundred of times.

 

How does that help clutch shudder?

Are you speaking of the clutch hydraulics?

 

The transmission fluid. In my MT vehicles I change the fluid every 30k and notice improved feedback from the whole system every time. If the fluid is contaminated or heat cycled too much this is a much cheaper option than replacing the clutch/flywheel and that may be all the repair it needs. Plus it's generally very easy to do on any MT.

 

I like to change the MT fluid often but I can't say I've ever seen that affect anything to do with clutch shudder.

 

Clutches and brakes work by transferring some friction material to the flywheel / rotors. Sometimes the material transfer is uneven. You may have seen the imprint of a brake pad on a rotor. That is usually caused by a panic stop where someone just kept their foot in it afterward (doing that often can lead to warped rotors).

This uneven transfer can be one of the causes for shuddering clutches and pulsing brakes. An easy thing to try is slipping the clutch to clean up the flywheel.

 

This is why I said it could also be a warped flywheel. Driven vehicles with both issues, and sometimes old fluid makes the trans shift like crap when it's cold. If fresh fluid doesn't fix it, then the flywheel will likely need resurfacing at a minimum. But fluid is cheaper than even a diagnosis and might fix the issue. The OP wasn't even sure if that was his issue so I wanted to bring up something he might not consider.

 

I did that on my SCCA ride too, with good synthetic. Certainly improved shifting as I improved brand selection.

I agree.

 

it looks like in another post, you have a steep driveway and are having to back up in it. I think the MT's are notorious for having a tall reverse gear. I am wondering if you are having to slip the clutch a lot and often, consequently warping the flywheel and/or damaging the clutch material. As @tonered mention, try cleaning it up by riding it.

 

This shutter you describe is something my truck has done since day 1 on cold damp mornings. Maybe I was too rough on the clutch the day before and put it away wet

5 years and 81,000kms and it hasn't gotten worse. It will still do it on cold damp days. After a couple engagemants it is gone. I wonder if it has anything to do with the accumulator... maybe one day I will fix that and see....

 

Good point. We could potentially do 40mph in reverse. Kinda silly.

The 2Lo Mod (2LM) is spectacular for taking wear out of the equation.

https://www.tacomaworld.com/threads...-2wd-low-range-for-the-3rd-gen-tacoma.614743/​

 

Mine shudders if I don't give it enough gas when accelerating from a stop and has done so since new. I've also kindof just attributed this to the accumulator. 42k miles here. Sounds like you may be in a different situation though, being that it's something new to you.

 

The accumulator would typically just give you a lurching kind of shift, not a shudder that feels like a vibration.


If folks are getting going at a very low RPM, they could be feeling the individual piston power pulses. But if it is consistent, I'd still start with uneven material transfer as the easiest, least invasive test.

 

I used to have shudder when starting up hills. Removed the clutch fluid accumulator and my clutch is normal now.

https://www.tacomaworld.com/threads/mt-accumulator-delete-mod-adm-and-bs-thread.568303/

 

Hmm, lots of interesting thoughts. I'll update if I find out what's causing it or if I do anything to makes it go away. It's so inconsistent that diagnosing it is going to be a PITA.
I do have the 2LO mod btw, unfortunately I did smoke the crap out of the clutch backing trailers up driveways several times prior to getting this installed (ok, I didn't LITERALLY "smoke" it, but it was pretty darned ugly).

Edit: I also removed the accumulator after 15k miles. That thing is cancer. I blame 90% of any inconsistent wear patterns on the clutch/flywheel on the accumulator alone.

 

Yeah I'd say lurching describes it better. As compared to something like torque converter shudder which I've experienced and that is like hitting a rumble strip.

 

Good stuff!

@Firn has a machined disk that is easy to swap in. He has a thread in the BST section.

Otherwise, dremeling that PoS will take care of it.

 

I have the bent line. Just have been way too lazy about it.