Transmission Noise in Neutral After Redline MTL

[98JettaBioDiesel]

Recently finished a complete engine rebuild on my 98 Jetta TDI (YIPEE).
Replaced clutch with Sachs unit, new TO bearing and output shaft/rear seal. Replaced trans fluid with 2qt Redline MTL.

The trans now makes a somewhat disconcerting rattling noise in neutral, which stops if I depress the clutch - about 1/2 way to the floor. Because of the amount of travel on the clutch pedal I get the feeling this isn't clutch/TO bearing related - plus the sound is wrong.

So I get the feeling it's internal trans parts (bearings - yikes?), but strangely increasing the RPM doesn't seem to change the pitch of the sound - so one of my car nut friends thinks it's more of a rattle.

Wondering if the different (thinner?) MTL fluid could be related, or if anyone out there is familiar with this condition???

 

[paramedick]

I suspect that you put in a VR6 unit and flywheel? I get this rattle all the time since my clutch replacement.

The MTL had nothing to do with it. Wasn't even in the car when the clutch was changed. It started when I drove it out of the garage at Jon's.

 

[Ralphy]

I suspect that you put in a VR6 unit and flywheel? I get this rattle all the time since my clutch replacement.

The MTL had nothing to do with it. Wasn't even in the car when the clutch was changed. It started when I drove it out of the garage at Jon's.

Same thing here. I was told that we should have used the TDI disk with the VR6 pressure plate. Springs on the TDI disk are bigger to avoid the rattle b/c this engine have more vibrations...

 

[98JettaBioDiesel]

Hmm, I don't think it's a vr6 pressure plate. Got it from Frank Irving along with one of his great heads and friendly advice. Still have the box: Sachs SD80047 (also 0121 141 031D) used my original flywheel.

 

[mopower]

Shouldn't you be using MT-90 for the correct fill in these transmissions? I believe spec calls for G50 or G51 which is a heavier gear oil.

 

[RIP TDI]

Same thing here. I was told that we should have used the TDI disk with the VR6 pressure plate. Springs on the TDI disk are bigger to avoid the rattle b/c this engine have more vibrations...

Does anyone have confirmation on this? Has anyone used the VR6 pressure plate w/ TDI disk?

BTW, Sachs # SD80047 is a VR6 disk.

 

[Jon Linn]

I get the same rattle as well. Ever since I switched to the VR6 clutch and flywheel. I believe I am also noticing a little slippage as well in 3rd gear. I think next time I will try the South Bend Clutch over eurospec.

 

[RIP TDI]

I have never read on this forum that the solution to the reported gear rattle w/ VR6 clutch is to use the TDI disc. It makes sense that it would.

If that does solve it and there are no compatiblity or durability issues associated with the TDI disc (vs. the VR6 disc), this information should be disseminated on this forum as well as to all the TDI vendors that are selling the Sachs VR6 kit (that include the VR6 disc).

 

[98JettaBioDiesel]

Shouldn't you be using MT-90 for the correct fill in these transmissions? I believe spec calls for G50 or G51 which is a heavier gear oil.

From what I've read, some prefer MT-90, some MTL, some 50-50 (quart of each). I wondered if the MTL, being thinner, might be "noisier".

I hadn't considered the noise was the clutch disk itself, but it sounds like this may be a common complaint with the VR6 clutch. I believe my new disk is NOT VR6 (per my SACHS p/n quoted above).

 

[RIP TDI]

. I believe my new disk is NOT VR6 (per my SACHS p/n quoted above).

Nope. Both your Sachs and VW numbers are for a VR6 disc.

 

[Ralphy]

The item that makes our new clutch able to handle more torque is the pressure plate, not the disc. The TDI clutch disc gives the same friction coeff. between the flywheel and the pressure plate, but have different springs on it compared to the VR6 one. I was told by a specialised VW shop's mechanic, who makes a lot of clutch conversions, that this rattle comes from the thinner springs on the VR6 disc (not designed for the TDI motor vibrations), and that one of his customer even had a failure of the disc springs and was not able to engage clutch anymore. The way to go is to keep a TDI disc when we change the clutch. Those informations were given to me by a trustable VW mechanic.

I have this noise since my clutch conversion. I also later changed my trans oil to Redline MTL to help my second gear synchro. No change on noise but better shifting during winter. No relationship between the rattle and MTL oil!

 

[RomSL]

Any new information that rattle is caused by VR6 disk and not by SMF?

 

[sfierz]

I don't know, my trans rattled before (with original clutch) and it rattles now with new Sachs clutch and PP. I believe I used VR6/TDI, but I am not sure.

Here's the part number I used: Sachs KF78701 from World Impex.

 

[White Crow]

If you installed a SM flywheel is is going to rattle no matter what disk you put in it because the disk is turning with the flywheel ie. engaged in neutral . The DMF ideal was to reduce the rattle. Bottom line if it's a SMF it will rattle in neutral no matter what you do. No one spends much time in neutral any way enjoy the positive results of a SMF and forget the rattle it does not hurt a thing.

 

[sfierz]

Exactly--this is what I have been doing. Hey, isn't that why VW put a stereo system in? I just live with this minor annoyance and enjoy the great shifting and longevity of a manual clutch. The original died after 230k miles!

If you installed a SM flywheel is is going to rattle no matter what disk you put in it because the disk is turning with the flywheel ie. engaged in neutral . The DMF ideal was to reduce the rattle. Bottom line if it's a SMF it will rattle in neutral no matter what you do. No one spends much time in neutral any way enjoy the positive results of a SMF and forget the rattle it does not hurt a thing.

 

[veedubyoo]

I have the same rattle about 50% of the time...I find if I press the clutch in and release it agin slowly it goes away. Couldn't tell you what it has for a clutch though...the cars an enigma..and it's new to me.

 

[Ralphy]

If you installed a SM flywheel is is going to rattle no matter what disk you put in it because the disk is turning with the flywheel ie. engaged in neutral . Bottom line if it's a SMF it will rattle in neutral no matter what you do.

I think that most of those who complaint of the rattle did'nt have that sound before changing the clutch, and without changing their flywheel that remains a SMF. Annoying, especially when idling beside a wall...

 

[RomSL]

If you installed a SM flywheel is is going to rattle no matter what disk you put in it because the disk is turning with the flywheel ie. engaged in neutral . .

How many MKIIIs came from the factory with DMF? How many MKIIIs start rattling after stock clutch replacement with VR6 one?