RPM acting funny after clutch replacement

Hi guys,

I just had a family mechanic replace the clutch on my tacoma with 100k. It started slipping and since i bought it used, i have no idea when was the last time it got replaced. Anyways, after the clutch was replaced the pedal felt smooth and it grabbed super nice. However, after about 100 miles into the new clutch i noticed when i first turn the truck in the morning, the rpms just stay around 700 and do not jump to 2000rpm when engine is cold. I also feel the pedal vibrate, as if it is engaged all the time, usually when im on the highway . "not a lot" but i do notice it. I have read in some posts where some of you recommend not preloading the clutch. Sorry for the NOOB question, but what exactly does that mean?

I was present when the he replaced the clutch and noticed everything went how it supposed to.

Any advice would be appreciated it.

 

One easy test. Crank it up. Put it in neutral and wait a few secs. Quickly put it in first (or any) gear and see if it goes in easily. If it doesn't, the clutch is dragging and trying to spin the input shaft. This makes the synchros work hard to equalize rotational speed so gears can engage. Also, check to see if the idle speed is different in neutral with clutch out, and in gear with clutch in. There will always be a tiny amount of drag, but you should not be able to notice it. There is also a different version that uses reverse since it has no synchro. Put in neutral and release clutch. This spins up the input shaft and clutch. Press pedal to floor and wait for 6-10 seconds. Quickly shift into reverse. If you hear a grind, the input shaft is still spinning. I can't give you a more accurate time than 6-10 seconds because this depends on a lot of things including clutch diameter, the weight of the clutch and pressure plate, etc. If after 10 seconds you still feel the gears grind or even if they just don't engage smoothly (you can feel the teeth have to adjust speed to mesh) then the clutch is not releasing all the way. This could be either end of the hydraulic circuit or even just low fluid.

When you say you feel something in the clutch pedal, that sounds like a potential throw-out bearing issue. Did he replace both the clutch and TOB? While the clutch pedal is pressed, the TOB is under a significant load pressing on the pressure plate fingers to disengage the clutch. If the TOB is going out you can sometimes feel it. Also are you SURE he torqued the pressure plate to the flywheel correctly? If the bolts are not tight, they can let the pressure plate wobble a little and that will be directly felt through the clutch pedal as a pulse or vibration...

First step is to try to more specifically identify where the problem is, the above will get you started.

 

You sir, are the man. I will check this out tomorrow morning.

 

The throw out bearing was replaced together with the clutch. When he showed me the clutch, he said it still had meat on it. the problem was the pressure plate. It was scratched.

 

That raises another question. How did it get scratched? Something wrong with the clutch disk itself (i.e. one of the springs pop out or a rivet break loose, etc?) It is pretty hard to get scratches there, particularly ones that affect engagement, unless some sort of foreign object gets in and causes damage. Part of a finger can break off, there's all sorts of things that might "let go" and cause damage. I hate fixing something without knowing what the cause was, as sometimes you only fix a symptom, not the original problem that caused the symptom. Slipping usually is not the result of a scratch, a scratch would likely cause chatter more often than any sort of slippage. Of course losing springs from the pressure plate would be a problem since it would then press less to stop slippage.

 

I'm sorry for getting back at this a month later, but I just got around it. I've come to the conclusion that the culprit is or could highly be the throw out bearing. I am sure it was replaced, but searching around in this forum I found a few members with similar issues. My next step is to call aisin to check if they want to cover the pilot bearing or if they are willing to send a new kit.

A few people have said resurfacing the flywheel is an option, and this wasn't done when changing the clutch.

Moreover, some peope say just to deal with the chirping since it won't cause long term damage

 

I can't imagine the pilot bearing causing a chirping. A TOB will do it for sure. Resurfacing flywheel during clutch replacement is my norm. I violated it once with my daughter's mustang and got to take the tranny off a second time to get rid of the chatter...

 

Yea man, now I have to take anything apart again. Lesson learned. Now I gotta wait a month to get this done since it's busy season for me. I hope nothing fails till then. Meanwhile, I'll just ignore the chirping.

 

TOB will rarely strand you. But they can make one hell of a racket if they seize up. The flywheel resurface is just annoying when the clutch chatters, but won't really damage anything if you don't go nuts...