Strange clutch shudder (when pedal depressed..)

[Numa]

Hey all,

I've trolled a fair bit through these forums and I seem to be having a possible problem that is the reverse of the normal issues as when my car is cold(ish, it can last for half hour to an hour) and I depress the clutch to change gears I get a strange mechanical shudder, it only happens when my foot is 85%+ to the floor and isn't consistent in the slightest as sometimes it's fine.. This noise will keep going as long as I have my foot depressed and can be heard outside of the car, the more it warms up the quieter it gets until it eventually goes away.

As I've only just bought the car I can't be sure what condition the clutch is in but there is no slippage or any shuddering at speed, only when my foot is on the clutch pedal..

I have a '99 VR-4 Legnum 5sp manual. 51k km's and for the most part the car seems to be in very good condition. The only mods I have noticed are a cat-back exhaust, turbo timer and some dumpy suspension I'm having replaced this week.

I've never owned an AWD so as far as I can tell this may even be normal!

Anyway any help would be appreciated as I don't want to go out and spend the money if I don't need to.

Numa. ^^

[Adam.Findlay]

could be your clutch release bearing on its way out, is is a violent shudder or more of a mechanical grinding whining noise.

[Numa]

It's not overly violent, more of a mechanical grinding noise. There is no whining/screeching but I can feel the vibrations through the clutch pedal. It sounds/feels like something is trying to move but is only able to move a bit. That being said though there is no adverse effect when changing gears because of it.

[Nick Mann]

It's not an issue I've come across before, but Adams suggestion has to be a good one. I take it the issue is not as the clutch is slipping? If it is an aggressive puk style clutch they can be very juddery. You'd notice that a lot when pulling away uphill though, or slow speed maneuvering.

[Adam.Findlay]

nick is right, very agressive clutches can shudder when starting off in first but as he says it shudders when holding the clutch past 80 percent open, i would say it is in my opinion the clutch release bearing based on the information given, if you can get a friend to help you have the engine at a fast idle and get someone to actuate the clutch pedal when you listen under the bonnet, if you hear a grinding noise coming from between engine and gearbox it will most probably be release bearing.

[Numa]

nick is right, very agressive clutches can shudder when starting off in first but as he says it shudders when holding the clutch past 80 percent open, i would say it is in my opinion the clutch release bearing based on the information given, if you can get a friend to help you have the engine at a fast idle and get someone to actuate the clutch pedal when you listen under the bonnet, if you hear a grinding noise coming from between engine and gearbox it will most probably be release bearing.

Thanks for that info, at least I have somewhere to start now! The clutch is surprisingly grippy but this noise only happens when I press it in, as soon as I'm in gear it's silent again.

Is changing the bearing normally a long or expensive process? I'm getting some work done to it this week so will approach them about it.

**EDIT**

Oh and nice sig picture Adam, my VR-4 looks very similar to yours it would seem. Although my rear is much lower then the front which I can't wait to have fixed!

[gareth001]

Is changing the bearing normally a long or expensive process? I'm getting some work done to it this week so will approach them about it.



If you are listening in the engine bay and can't find exactly where the noise is comming from, get a long screwdriver and place the metal bit on the top of the gear box and then listen through the handle, you will be able to hear any rattling/grinding going on within the box. As a comparison listen like this to the engine block. A slight rattle will normally mean there is a slightly loos bearing within the release bearing - as you know the function of the clutch will not be effected. It's only if it starts getting rather loud and clunky sounding that you need to do something about it like NOW, as the release bearing could quite easily just explode.

Now for the bad news unless you know a friendly machanic/are good with hands on work. The actual bearing is housed within the gearbox behind the flywheel and clutch - this unfortunately is about a day+ work to swop out as the transfer box has to be removed, the engine has to be part dropped to allow room for the the very heavy gearbox to be taken out. I think Mitsi time is about 8-10 hours to do this, but of course this is on a ramp. If you have a look on the forum there is a guide of how to do this on the floor - but personally I did it on a ramp with help (needs two to move the gearbox around) and it took all weekend.

Oh the release bearing itself is only about £35 UK, so could be around $60-80 AUS, but you may need to replace the clutch depending if you can get the old one off or not without breaking it. And of course you will need new oil for most of the front part of the engine. If you do take the gearbox off, it's also a good time to replace the oil seal behind the flywheel, again a cheap part, but being behind the flywheel expensive in labour to replace.

[Adam.Findlay]

to bad you all the way in auzzi because myself and associates from around here in christchurch have got quite fast at removing gearboxes and refitting them.
even with listening through a screw driver it can be difficult to hear as the release bearing isnt in direct contact with the gearbox casing, i guess if you can get your hand or a screwdriver or some kind of mechanics stethascope to listen or feel the end of the clutch release lever you will be able to feel/ hear the grinding bearing (if that is the case)
but if you dont have the know how to remove the transfer case and gearbox and refit them then paying for a new clutch ontop of the labour charges might be worth it as removing the gearbox is a big job and doing it again 6months to a year down the road could be a major frustration. but thats up to you
cheers. about the picture comment too, relativly standard on the outside my car except being lowered on some tein type flex adjustables, vented guards and some evo 9 wheels

[Numa]

haha ah I don't need a screwdriver.. I recorded it for you, it's much louder underneath the car although in this video it's quite loud where it can be fairly quiet and then goes away completely after a while.

http://www.youtube.com/watch?v=bHBUYL5M6Jo

I take my foot off the clutch at the 1s mark and then back on again at the 3s mark. I get the feeling I may need to replace it soon :p

[Numa]

Haha yeah, bit too far to swim :p

Well it turns out I don't need a screwdriver to hear this baby now. I tried to reply yesterday with a link to something I uploaded on youtube but it hasn't been verified so it's in the nether. If you u-tube 'VR-4 Legnum Clutch sound' it will come up though, I recorded underneath the car and wow, it's loud. Getting it checked out in the next week or two. It's bad enough it may even be covered under warranty, I hope so anyway!

I looked into Tein covers, wanted to charge me about 2k for them O.o

I love relatively stock looking cars (with just a few touches), much classier.

[Adam.Findlay]

hard to hear via video im still sticking with release bearing

[Numa]

Yeah it is a bit, if you wait until the last 2 seconds or so of the video I take my foot off the clutch and what sounded like a rough idle is actually the clutch :p

But yep sounds like you could be spot on, will let you know in the next few weeks what happens!

Oh if you start from 7s you'll hear me take my foot off right on 10s. The car is still running at that stage too.

[Numa]

So I have finally found someone willing to take apart my clutch and have found out that it wasn't the thrust bearing at all. When the dealership replaced the clutch kit before selling it to me they had trouble finding a standard Legnum kit so went to a clutch 'specialist' and were given an Evo kit that was 'close'. That ratcheting sound is actually the pressure plate grinding the inside of my bell housing into a thin paste :oops:

http://i1224.photobucket.com/albums/ee361/Jonathan_Regan/IMG_9023.jpg (how do I make this into a pic?..)

On the left you can see where it has been munching away on some metal goodness.

Needless to say I'm less then happy, if they fix this then I'll leave them alone, if not then I'll be contacting consumer affairs. What a pain :(

[Adam.Findlay]

there has been many debates about how safe it is to use evo clutches on vr4 flywheels. I always said dont risk it and here is the proof!

[Numa]

Haha, if nothing else I'm good for proof on what not to do! Basically there is just no room in between the gearbox and pressure plate so as soon as I dis-engage the clutch it's pushing it directly onto the bell housing. if the bell housing was slightly larger it probably wouldn't be an issue.

I'll find out shortly what they intend to do. They're trying to source a Legnum kit but who knows how long that will take.. *sigh*

[Adam.Findlay]

you can but one of nick mann's spacers and use an evo flywheel with your existing clutch or just get a vr4 clutch

[Numa]

If I was still in the UK I would have considered it :)

Thankfully I just got a call saying they managed to track the VR4 clutch down and they are putting it back together. Now to see if I can get the money back from the dealership...

I think one of the problems over here is that the VR-4 is a very mis-understood car as it doesn't have the following it does in the UK and NZ. A real shame as this is an awesome beast to drive.

[Adam.Findlay]

they have a huge following in oz. its just not as well known as other common turbo cars such as skylines, evos etc

[Numa]

Try telling that to the mechanics that refused to work on my car because it was too complicated, I've never been turned away before :( (and this mechanic owns an Evo and works on European cars a lot)

At least this problem is being fixed though, next step is to get my teins on :)

[Gly]

to complicated??
its no different to an evo apart from the extra 2 cylinders.

same gear box more or less, same transfercase and rear diff.

i would never let anyone thats not confident work on my car.

anyway...
should have used a magna/diamante kit

exedy mkb-7223-hd

that is the normal aftermarket kit supplied for the 8th gen vr4 and has been used numerous times without issue.

[Numa]

I hope that's what they've changed it to then.. It's times like these I wish I knew what I was doing around the insides of an engine bay...