DMF rattle... fixed itself?

[ShadowSplicer]

Hey everybody! First post here, after a solid year and a half of stalking the forums for info before I bought my first car.

Now, my lovely DSG has started doing strange things. About 6 months into ownership, it slowly started rattling when starting from a standstill, and slowly got worse. I noticed a slight clunk while downshifting automatically (not in manual), which wasn't bad, but it was a change. I did tons of research as the problem sounded worse, and decided it sounded like a shredded DMF spring.
I took the car into a local import shop, (long story), they said it didn't sound bad, and usually the DMF didn't go on these cars. They didn't want to have me spend $500 in labor to take it apart, just to have it not be broken enough to fix under my (Chevy) dealership warranty.
About a week ago, suddenly, the noise STOPPED. The clunking seems to have gotten a bit better, as well.

What...do I do? Should I leave it alone? I can post videos of the noise later tonight if you guys are curious. I don't want to foot a tear-down bill if I'm not 100% sure it will be "broken enough" to be covered.
Thank you everybody! Hope I can get some good advice.

 

[GIACUser]

Well posting a video of a problem that has gone away won't do much.

How many miles on the car? Since its 10yrs old I am going to guess that it is north of 100K mi. First thing to check is the trans and motor mounts. Once the first one fails then it puts undo stress on the others. If the trans mount is really shot is could have caused a rattle and some banging on downshifts as the trans was not being held in place.

 

[ShadowSplicer]

Well posting a video of a problem that has gone away won't do much.

How many miles on the car? Since its 10yrs old I am going to guess that it is north of 100K mi. First thing to check is the trans and motor mounts. Once the first one fails then it puts undo stress on the others. If the trans mount is really shot is could have caused a rattle and some banging on downshifts as the trans was not being held in place.

Bought the car at 129k, problem started at 136k, stopped at current 140k. I have a video of the actual sound it WAS making (139k miles). If it's the DMF (which sounds like that, from previous videos) I don't know why/how it could have stopped.

Any good articles on replacing/checking these mounts, that you'd recommend? I've been working on cars for a few years, and have some tools handy.

 

[GIACUser]

Bought the car at 129k, problem started at 136k, stopped at current 140k. I have a video of the actual sound it WAS making (139k miles). If it's the DMF (which sounds like that, from previous videos) I don't know why/how it could have stopped.

Any good articles on replacing/checking these mounts, that you'd recommend? I've been working on cars for a few years, and have some tools handy.

Changing the mounts is not difficult. Here is a video on how to change the two major mounts. Trans/Engine.
DIY LINK
PARTS LINK


There is also a set of smaller mounts that should be changed at the same time. Often referred to as dogbone subrame and dogbone. The two mounts above support the weight of the engine and trans. This third mount set controls their twisting motion that occurs under accel or decel. Needless to say if this one goes bad the motor is going to twist excessively and that twisting will over time help trash the two major support mounts.

Here is a link to what a bad one looks like.
Viewed from under car.
LINK

Unfortunately the dogbone subframe bushing is pressed into the subframe.

As a DIY you can remove the subframe plate and have it pressed out if you have a properly sized press and then having new one pressed in. If you do this have new bushing on dry ice or well packed ice (easier to press in).
Your car will also require a front end alignment after this procedure.
DIY LINK
PART LINK


Or you can take to VW and they have a special factory only tool that can remove and replace the bushing without removing the subframe plate.

Or if the bushing is not cracked or split yet you can do the easiest thing which is to get a dogbone insert to reinforce the bushing. If its cracked don't bother with this. At your mileage I would probably just replace all 3 mounts.
DIY LINK
PART LINK

As for the dogbone mount you can just buy the arm with the bushing pressed in place. In the videos above is info on R&R.


Usually high mileage or modified cars run into the mounts going bad either through just the rubber in the bushings just drying out over 10 years or in my case after increasing the power to 335whp the stock bushing split very quickly. Hopefully the DSG is not having issues. Just keep it serviced every 40K miles (fluid and filter change). Having the DSG pulled and having just new clutches and seals put in and if you needed it (flywheel) will probably end up being around 3K by the time you are done. You wouldn't want to open up a 142K mile trans, spend all that labor and not replace the clutches. (opinion only).

 

[ShadowSplicer]

Changing the mounts is not difficult.

Had no idea, super simple. I will be checking those out once I get over this nasty cold. I haven't had to hold the engine/tranny up by jack yet, so I'm a little iffy on where to put it. I feel like putting it on the oil pan, like in the video, isn't the greatest idea.
I have put in an ECS dogbone insert, and didn't notice anything funny about the mount when I got it in. So I'm safe there.

Usually high mileage or modified cars run into the mounts going bad either through just the rubber in the bushings just drying out over 10 years or in my case after increasing the power to 335whp the stock bushing split very quickly. Hopefully the DSG is not having issues. Just keep it serviced every 40K miles (fluid and filter change). Having the DSG pulled and having just new clutches and seals put in and if you needed it (flywheel) will probably end up being around 3K by the time you are done. You wouldn't want to open up a 142K mile trans, spend all that labor and not replace the clutches. (opinion only).

Well, the warranty I paid through the nose for (in case something exploded) will cover broken parts, but not worn clutches or flywheels... I don't have nearly 3k right now, so I sure hope that it's just mounts. Or that it breaks completely before my warranty is up; 1 more year or 9k more miles.
If I got it apart, I'd replace the clutches, definitely. I'd probably go all-out and make payments. Last resort, though. I'll post that video, check those mounts, and post back.

Thank you for all the info GIACUser, super helpful! :thumbup:

 

[ShadowSplicer]

Update: 2/17/17 - noise is back!

Usually high mileage or modified cars run into the mounts going bad either through just the rubber in the bushings just drying out over 10 years or in my case after increasing the power to 335whp the stock bushing split very quickly. Hopefully the DSG is not having issues. Just keep it serviced every 40K miles (fluid and filter change). Having the DSG pulled and having just new clutches and seals put in and if you needed it (flywheel) will probably end up being around 3K by the time you are done. You wouldn't want to open up a 142K mile trans, spend all that labor and not replace the clutches. (opinion only).

A bit of an update here. :help:
I'm bringing my car to a performance shop that will do my 140k DSG service on Tuesday. I decided that it definitely isn't the transmission, as I drove a bit more and checked out my mounts. The primary side engine mounts look a bit old and the one under the battery is a bit torn, however not bad at all.

I did however think of something else! A friend noted that the sound was very similar to a problem he'd run into before; a broken/pinched flex pipe. The rattle could very well be the engine/tranny rocking back against the exhaust, and the flex pipe is pushed out of shape and rattles on acceleration. Any thoughts on this? The noise came back unprovoked, and I got a GREAT video of it this time.

https://storage.shadowsplicer.com/flex_rattle.mp4
(This video is hosted on my own webserver, hope that's okay with the forum rules. Also, I never consider that handheld filming while driving is okay, but this was a controlled area!)

 

[ShadowSplicer]

The rattle is getting worse. I've been so busy lately, zero time to start taking things apart. Does ANYBODY have an opinion on the video I posted? Any suggestions on cause?

 

[Das Gespenst]

Video takes forever to buffer so I couldn't get a good listen, only plays like 2 seconds at a time. It doesn't sound like DMF, I had mine start failing and am familiar with the sound. From what I could hear you're in the clear on that one. Very possible it's the flex pipe in your down pipe.

If you can physically see a tare in your trans mount it's done for, I would highly suggest getting new mounts. Checking the flex pipe is easy, just Jack your car up and look up right behind your subframe. The other thing it sounds like is your cat loose in the housing, I also went through that but eventually got a CEL and car would run like crap.

 

[ShadowSplicer]

Video takes forever to buffer so I couldn't get a good listen, only plays like 2 seconds at a time.

My bad. It was shot in 4k with my phone, I downsampled it to 960x540. :eyebulge:

The other thing it sounds like is your cat loose in the housing, I also went through that but eventually got a CEL and car would run like crap.

I wouldn't doubt it. This car was in good repair when I found it, but I feel like there were a lot of zip-ties involved in the process before they replaced things with OE parts.
Thanks man, puts me more at ease. :thumbsup: