clutch shudder

[patcal]

I have a clutch shudder on my 95 Outback. It only happens when the car is cold. As the car warms up, the shudder slowly fade untill all is smooth. Should I start worrying or is this common in Subies? Thanks.

[WRXdan]

Very common. My WRX had this. I believe there is a TSB outlining this problem.

[fishbone79]

Often one will get shudder if the pressure plate housing and the flywheel are a tiny bit loose… because of their density differences, they expand/contract at different rates when they are cooled or heated. They will arrive at a level of relative stasis when the car is warmed up because the temperature remains more or less constant. It is not necessarily a sign that they are loose… I have never personally seen one become terribly loose, but I know it can happen. From what I understand, this phenomena, although rare, does occur when the clutch and flywheel are far over tightened, which doesn’t allow the slight amount of movement necessary. Also, when your car is cold, everything is slower; grease is thicker as well as oil and lube. I am of the opinion that running a car cold accentuates any of the small imperfections it may have (especially those solved by proper lubrication)… a small amount of uneven wear on your flywheel, pressure plate or clutch may be brought out when the car is cold because the engine’s revs are much slower and the transmission slows down much more between shifts. Those are just thoughts, the problem could be completely unrelated, however. Try warming up your car, and then driving.
Cheers!

[professor]

try switching to a good synthetic lube, like Redline MTL. It has much lower viscosity when cold than mineral oils, and helps with all manner of cold gearbox issues (bad cold shifts, etc).

[entirelyturbo]

professor, it has nothing to do with the gearbox.

There is a TSB for clutch shudder for some newer Subaru 5MT's. I recall the final conclusion being that Subaru admitted to using substandard materials in the clutch disc.

Really, if you pay attention to your driving, you can prevent it from happening. I don't slip the clutch as much as most people, I just release it enough to get the car moving, then let the car catch up to the engine. My clutch was replaced about 28k miles ago, when this TSB was really hot.

[professor]

the real answer is that Subaru clutches are generally sucky, and some suck worse than others. Mine is fairly new OEM and it is easily the worst clutch I've ever had on a modern car, weak and grabby all at the same time, and damn hard to consistently be smoooth.

The only guaranteed solution I've heard from other subaru owners is to take the clutch and flywheel off, throw them away, and replace with aftermarket. That seems to do the trick.

[Legacy777]

I've got a wrx clutch on mine, and while it's not super smooth, it's not bad. Plus I've also got a LW flywheel which doesn't add to the smoothness.

Eitherway, I don't mind it. It grabs good, and I can smoothly slip it when needed. It is a little more grabby when cold.

[patcal]

Thanks for all the input. I think I will just live with it untill something else happens.

[evolutionmovement]

I have whatever aftermarket one my mechanic put in and only got shudder very occasionally. I no longer get it since replacing the engine and tightening everything to FSM specs. The clutch is very repeatable and easy to drive smooth, but the feel isn't great so it's not for learners (like I'd let someone drive my car anyway).

Steve