Is this acceptable? Rattle after clutch replacement

Hi.
Today I replaced stock DMF setup with used SMF G60 flywheel and New VR6 Luk clutch kit. The clutch engages smoothly, doesn't slip, in general I really like its behavior. However, one thing really disappoints me - the transmission now rattles at idle sometimes. Sounds like a spinning wheel-bearing that has big play in it. When I disengage the clutch the noise disappears. At the beginning I thought that this is regular SMF chatter that people get when they replace DMF with SMF kits, but in my case the rattle is not constant. Most of the time the clutch doesn't make noise at idle at all in either engages or disengaged state, but occasionally in neutral it starts rattling. It rattles a lot when I just crawl in the first or second gear at idle. It may rattle for several seconds when I turn on AC or when I press clutch pedal several times. What could be?

Here's the video.
The temporal character of the rattle is the best heard at 25sec. and further.
http://www.youtube.com/watch?v=aapoAW0it80

Normal , some are louder then others but all rattle some. It is a small price to pay for a much stronger clutch setup.

The rattle is caused by the gears in the tranny clicking together back and forth while they spin unloaded in neutral with the clutch out. With the stock DMF setup, the rubber band effect of the DMF at low RPM dampens the engine's strong torque pulses at idle to smooth out the torque input to the transmission. With the G60/VR6 clutch setup using an SMF, the SMF doesn't provide the damping at low RPMs provided by the DMF and the strong torque pulses at idle get transmitted to the gears. The gears have a little bit of backlash and torque pulses rattle the gears while they spin unloaded.

It makes the car sound a little more truck-like at idle but does no harm. You will also notice the sound will be louder when everything is warmed up to temp due to the gear oil being thinner when hot. Also what you are using for gear oil and how full the transmission is will affect how loud the rattle is.

It's normal with the G60/VR6 SMF clutch setup and nothing to worry about. Like Birdman said it's a small price to pay to have a much stronger clutch setup.

Good luck.

Thank you for the detailed explanation.
But why the rattle isn't constant? Like I said most of the time the clutch doesn't rattle.
A friend of mine has the same car with the same mileage and installed G60/VR6 kit (Sachs) that, unlike my car, rattles all the time while the car is in neutral and it does sound more like a little truck now.

I've contemplating a bit and to my mind possible causes of the rattle are:
1. disalignment of cranckshaft and gearbox primary shaft.
2. excessive play in gearbox primary shaft bearings.
3. axial runout of cranckshaft is bigger than that of gearbox primary shaft.

What do you think, guys?

yes

Ive got a similar set-up and rattle.

permanent rattle?

RomSL said:

I've contemplating a bit and to my mind possible causes of the rattle are:
1. disalignment of cranckshaft and gearbox primary shaft.
2. excessive play in gearbox primary shaft bearings.
3. axial runout of cranckshaft is bigger than that of gearbox primary shaft.

What do you think, guys?

Click to expand...

None of the above. The rattle is due to the strong torque pulses at idle being transmitted to the gear cluster in the tranny instead of being dampened out by the rubber band effect of the stock DMF. When using an SMF, you trade away all damping that was provided by the stock DMF. The rattle is actually the sound of the gears clicking together as each individual torque pulse rattles the backlash of the gears. They click with each individual torque pulse at idle. Smoothness and quiet operation are good reasons among others why VW would choose to use a DMF with the stock setup.

The tranny also seems to have a resonance at near idle RPM which makes the the rattle worse. The rattle goes away if you try nudging the engine RPMs up slightly above idle.

As for why some rattle more than others?

Possible causes:
1. Gear oil level: How full the tranny is with gear oil and what gear oil is used will make a difference. The rattle may be louder if the gear oil level is low. You may also notice the rattle being louder when everything is HOT compared to right after a cold start due to the gear oil being thinner when hot.

2. SMF weight: IIRC, you can use the OEM heavy SMF or a lighter SMF. The rattle will be louder with the lighter weight SMF so definitely go with the heavy SMF. I forget how much the stock DMF weighs (~ 30 lbs?) and I recall the heavy G60 SMF weighs around 18 lbs and the lightweight SMF weighs around 11 lbs. Even with the heavy SMF you're already trading away some flywheel mass.

Good luck.

n1das

all MK3 TDI have SMF and they don't rattle until Vr6 Pressure plate and disk are installed (and P.P is actually the same in both TDI and VR6 kits).


At the moment I'm doing a little research on this issue.
As I wrote, there is another car like mine that underwent clutch replacement. Same car, same mileage, same age, gearbox oil has never been changed in both cases. That car doesn't rattle, but it does constantly click in neutral with clutch pedal off, with the same frequency and magnitude. It stops clicking immediately once the clutch pedal is pressed and the clicking itself isn't bothering at all as it's permanent. Initially I thought that Vr6 kit was used too. I was wrong. The owner of that car used Sachs 3000 327 002, which is for Transporters T4, 84 Hp. So, we both used stock SMF, pressure plates are pretty much the same and don't play any role in dumping the vibrations. The only difference is a disk, the springs in the hub in particular.

RomSL said:

n1das

all MK3 TDI have SMF and they don't rattle until Vr6 Pressure plate and disk are installed (and P.P is actually the same in both TDI and VR6 kits).

Click to expand...

I find this interesting and strange. I'm curious what you find out.

So the only change made when upgrading an MK3 is the VR6 disk? The springs in the hub may be playing a part. Some closeup pics of each would be helpful.

VR6 MK3 Sachs 3000 384 001

SACHS 1862 393 031 Disk
SACHS 3082 231 031 PP
SACHS 3151 000 388 Bearing

TDI MK3 (1Z) Sachs 3000 332 001

SACHS 1878 043 141 Disk
SACHS 3082 231 031 PP
SACHS 3151 000 388 Bearing

Here's one interesting report too

https://forums.tdiclub.com/showthread.php?t=155260

VR6 springs supposedly are stiffer than TDI's are and that probably accounts for the rattle with VR6 Disk.

Luk uses different pressure plates in Vr6 and TDI kits. But, Luk VR6 pressure plate is used also in the kit for T4 2.4D 78Hp

RomSL said:

Here's one interesting report too

https://forums.tdiclub.com/showthread.php?t=155260

VR6 springs supposedly are stiffer than TDI's are and that probably accounts for the rattle with VR6 Disk.

Click to expand...

I was thinking the same thing too. With stiffer springs in the hub you have less damping of the TDI engine's (strong) torque pulses at idle. It's a tradeoff we've made to have a stronger clutch setup.

I have the SACHS G60/VR6 SMF clutch setup in my 02 Golf. It has the rattle. While it's a rattler, it's been trouble-free for more than 200k miles. My 05 PD JWagen has a South Bend Clutch stage 3 SMF setup using an OEM VW G60 SMF. It too has the same VR6 rattle.

Well, now it's a question: is VR6 clutch really stronger than MK3 TDI? We have the same clamping force, the same diameter, supposedly the same friction material (organic, right?) and all of a sudden VR6 clutch appears to be more robust. Why?

BTW, my original DMF Luk setup didn't slip with all modes in the signature. Broken DMF was the only reason why I changed the clutch.

Lighter flywheels make the rattle more than heavier flywheels. Last one I did was rattling terribly and I assumed it was a failing Dual Mass. I pulled it out ans oops! It was single lightened flywheel. I put in the heavy (22lb) flywheel and noise was gone.

If your is intermittant maybe you just have something loose and rattling. mechanics are human. Get under the hood or under the car while its making the noise, and pinpoint where its coming from.

CoolAirVw, what disk was used in that car? VR6 or MKIII TDI?

VR6

Vr6

Why did VW change there flywheel? With all the problems they had DMF why don't go back SMF? Sorry for jumping on your thread.

MonsterTDI09 said:

Why did VW change there flywheel? With all the problems they had DMF why don't go back SMF? Sorry for jumping on your thread.

Click to expand...

Is this a question for me?

CoolAirVw said:

Is this a question for me?

Click to expand...

.,

Yes

I didn't put in a DMF. I took out the lightened SMF and put in a stock weight SMF.

I re-read my post and I can see how you might interpret it that way.

For me I finaly found what cause the clutch ruttle...

Last year I done 1Z engine rebuild in one of mine B4 and also I replaced the clutch. I installed clutch disk from VR6 (LUK, part number: 021 141 031C). Engine was running perfect (almost everything inside was replaced), but at iddle it was horrible sound from the transmission side somewhere. Rattle like junk car when indling, but on freeway car drives very nice...
Few weeks ago I done my TDI conversion (GLX B4V), so when the engine was on the floor I desided to check the clutch, the previous owner (donor car I used) told me he never replaced the clutch. Clutch appear in good condition for me, so I desided to install the same TDI clutch disk (LUK, part number: 028 141 035B) but for experiment I put VR6 pressure plate (LUK, part number: 921 141 025F).
Started the engine... and ohhhh is sounds very quite. I drove this car for ~10 days, thinking maybe some comeup later... But so far no rattle at iddle, and clutch works nice.
So, if you thinking installing clutch on TDI from VR6 - install only VR6 pressure plate but clutch disk original TDI. Will be no rattle. Not familiar with flyweel replacement, maybe with lightened flyweel also will be some rattle (have not done this in the past).

fix?

so a disc with soft springs would take care of the rattling?

CrAzYDr1veR said:

so a disc with soft springs would take care of the rattling?

Click to expand...

Yes. TDI clutch disk has a little softer springs (and 2 springs less) if compare to VR6 disk.
I just swapped clutches in another two TDI's last month. I keep TDI disk and installed VR6 pressure plates. No rattle at iddle, very quite clutch and hold torq very vell.

Hi, just bought a b5.5 passat 130, all good until the other day i noticed when the clutch is out and the car in neutral there is a rattleing noise and when the clutch is pressed in, it stops. car has only done 89000 miles but i think its the original clutch. could it be the dmf or maybe i am noticing it more now because the weather is alot warmer and the oil in the gearbox is old??? there seems to be a little judder in netral when reving and holding on 2000rpm. could it be the dmf?

DM flywheel rattle?

I recently had a new Luk clutch and dual mass flywheel installed as the original clutch was slipping. Although the new Luk clutch works fine, there is a muffled rattle when changing up through the gearbox under fast acceleration. It happens for a split second, just as the clutch is disengaged before shifting up a gear. It sounds almost like a low 'growl' on the over-run as you throttle off and I suspect that it's caused by the DM flywheel oscillating against its spring stops.

As I said, it only happens under fast acceleration mainly in the lower gears. It doesn't occur when using gradual acceleration and changing up below 2K Rpm.

I never heard this with the original clutch, which was an OE Sachs unit. So is it possibly due to the design of the Luk flywheel - maybe the Sachs flywheel is better damped? Anyone else had a similar experience with the Luk clutch and DM flywheel? Do I need to worry, or is this normal?

Any comments would be appreciated.