Nicole

Friends of mine have a 968 convertible with Tiptronic that makes a strange noise from underneath the back of the car. Specifically, I think it comes from the area of where torque tube and transmission meet.

It's a clacking noise that's quite loud after a cold start, and then gets quieter, but doesn't seem to go away entirely.

The noise has been there for years, but recently intensified a bit.

The local Porsche dealer, where the car was serviced when it first started, told the owner there are "lose rivets at the flex plate". However, I browsed through PET for the 968 and to my surprise I could not find a flex plate listed anywhere.

An independent mechanic told my friend that he needs a new torque tube, etc for the cost of about $2000.

I would like to get some opinions on what this could be, and how to best proceed. My friend doesn't know much about car mechanics, and is not inclined to wrench himself.

If you know a reliable independent Porsche mechanic in Contra Costa County, CA, that would be helpful also.

Thanks!


PS: This thread is a continuation of a similar thread in the general 924/944/951/968 forum:
https://rennlist.com/forums/924-931-...ing-noise.html

User 41221

This doesn't sound like a flex plate failure (sounds more like a diesel engine clattering) and torque tubes typically don't "clack". It *might* be the torque converter that teh dealer was referring to, but I am not convinced. If the noise is present when the car is sitting and idling, I'd suspect the ATF pump. Was the car ever run low on ATF fluid?

Start by doing a thorough flush of the ATF system and make sure the strainer is cleaned out and see if effects the noise level. That will tell you a lot.

968workaholic

Look through the hole on the side of the bellhousing at the rubber dampner. It sounds like it is torn. There are stops welded in that hit against stops on the dampner which make a terrible sound.

Nicole

Thanks for the input! This sounds plausible, and I hope to check it out next time I visit my friends.

Is this something they can drive with for a while, or should this be addressed immediately?

968workaholic

The stops are made so that you won't be stranded if the rubber rips. Same setup is used on the rubber centered cluth discs in 944s. You can drive it but you run the risk of breaking the tabs off and being stuck, as well as having to get a new flywheel.

Nicole

I'm confused... Isn't the flywheel in the front, at the engine? The clacking sound is in the back, at the front of the transmission. Is there a similar rubber damper plate there?

968workaholic

if you are 100 % sure that it is coming from the back then it could be loose flexplate bolts. the more common problem is the dampner ripping. it could sound like its coming from the back but it may really be coming from the front. the only way to rule out the front is to look through the inspection hole at the dampner

User 41221

The flex plate is in the front by the flywheel (where the clutch plate would be for a manual tranny car).

Can you describe the clacking noise better? A flex plate failure sounds like a diesel motor clattering (at least to me), and isn't completely rhythmic. If its a rhythmic noise at the back of the car, I'd still look at the ATF pump first.

Regards,

Nicole

Yes, rhythmic, as if it would make the same noise with every turn.

So, you guys think this noise could "travel" from the front, and fool us into believing it comes from the rear. That needs to be checked-out. Not sure when I'm going to get up there again, but hopefully soon.

Thank you very much for the input! I will report back once I had another opportunity to hear it.

Tom Carson

some confusion with terminology here...

The drive plate is located between the REAR of the torque tube/driveshaft and the transmission. The Porsche PET manual refers to it as the 'converter mounting' while the Porsche workshop manual calls it a 'drive plate' (but many call it a flex plate).

Whatever, this is what the torque converter mounts to and I have experienced a clicking (or clacking) noise that was traced to it. Tightening a few loose bolts cured my problem.

btw...the damper is located between the flywheel and the FRONT of the torque tube/driveshaft. Both the Porsche PET and workshop manuals refer to the rubber damper as just the 'damper' (but many call it a flex damper). When it fails there is a lot of vibration with a thumping noise.

and as you can see there is confusion between flex plates and flex dampers all the time...

so I just did a search of the word 'flex' in the entire 968 workshop manual and it returned '0' instances.!

Nicole

Hi Tom: Thank you for clarifying those terms! You and my friends might well experience the same issue here.

However, the dealership said there were lose "rivets", while you report these are actually bolts that can be tightened.

In order to access the bolts at the "drive plate" - what has to be removed? And what tools are necessary to get to the bolts and tighten them?

Tom Carson

The torque converter mounts to the drive plate with three M10 bolts. There is also a clamping (collar) piece that has a bolt, securing it to the shaft. There's access to these bolts from an inspection/dust cover.

I was living in a flat in London at the time and brought it to a independent Porsche shop for regular service. I told the mechanic about the clacking noise. He told me he tightened the drive plate bolts and my problem was solved. I am not sure which or how many were loose.

There are 10 heavy-duty welded 'rivets' that attach the plate to the collar section. I can't see how they would ever work loose. If the plate needs to be replaced I would ask for the old drive plate to be returned...and post pictures of it if the 'rivets' are loose.

to see this check:

https://techinfo.porsche.com/techinf...68_KATALOG.pdf

page 78 of 350 and the part is # 2

Nicole

Awesome! That'll give me a great starting point.

I will try to do this in April, and report back.

Nicole

Update: Before I could take another look, my friends decided to take the car to a Porsche mechanic.

He disassembled the front of the transmission and found that the bolts that connect torque converter and torque converter mount were lose and have worn both the threads in the torque converter and the holes in the mount. Apparently, it's not a very pretty picture.

He also found the torque converter to leak a bit, and recommended to replace the "flex pate" a the same time. My friend says that is supposed to be the "flex plate" on the engine side of the torque tube.

The trouble is that the local Porsche dealer says the parts have to come from Germany, and there would be high express shipping fees. Now my friend is trying to see, if he can source the parts otherwise.

Specifically, the mechanic said he needs:
- Torque converter
- Torque converter mount
- Flex Plate (Is that what's called "Dampener" in PET?)

Are any of the above parts available as OEM parts?

Where should I direct my friend to, in order to get the parts fast at a good price?

Thanks!

Tom Carson

Yeah...while you are in there you may as well change the old damper (what PET calls it) with a new one:

http://www.vertexauto.com/ShowItem/2...20-%20944.aspx

and probably repack the CV joints.

If it were me, I'd go with used parts for the converter & mounting plate...but that's easy to debate and I'll stay out of it