[xmac911]

Recently bought a high mileage 1994 coupe in the Oakland CA area that makes howling noises in mostly in the rear at about 62MPH and above. I have to use earbuds with noise cancellation to drive on the highway. 

 

Joined the site to better understand the magic of torque tubes among other things I have never dealt with on a car. 

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[94SilverCab]

Welcome,

 

That's not the torque tube, that's the Pinion Bearing...JMHO.

 

Jay

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[lbpesq]

Well howdy Xmac and welcome to the forum!  I and my ‘93 Cab are just up the hill from you in the Montclair section of Oakland.  I’m attempting to put together a Bay Area fun run sometime this summer.   Check back here for more info.    Do you have a good local 968 mechanic?  

 

As for your noise, does it sound like a jet plane?   That would be a bad pinion bearing.  It is VERY common in our cars.   I’m at about 110K, (not sure as I recently experienced another common issue: melted odometer gear - waiting for some warmer weather to pull the dash and replace it along with a dash light LED upgrade), and have luckily not experienced the pinion failure (fingers crossed/knock on wood).

 

Bill

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[Roboman]

Welcome aboard Xmac, good luck with it all ....

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[Rap]

Welcome. Enjoy your ride!

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[xmac911]

Thanks for the warm welcome! I finally made it in.

 

I do most if not all the wrenching on my cars. This doesn't sound like a jet. I'll capture some audio when I get a chance. I assume that would be like the whine in rally cars at different speeds/rpm? I haven't been able to work on the rear end yet as I am replacing the radiator and both fans due to running really hot in stop-n-go traffic.

 

While I had the radiator off, I pulled the timing covers off and discovered the lower balance shaft appears 180 degrees out and the upper balance shaft off by one tooth. Waiting for parts now, I figure I might as well do the timing belt. 

 

Thanks Bill. Looking forward to a summer run once I know I am mechanically sound. 


...I know this is supposed to just be intro, but as a noob to torque tubes, what are the symptoms of a bad torque tube? How do you check it?

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[xmac911]

... searching the "What is that noise" forum now.

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[ds968]

The whine similar to a jet landing and taxiing on the runway is mostly on deceleration, and definitely pinion bearing , the tone at 60 mph + is a bit different , but could very well be that as well.    But know that some old tires can also “ howl “ at highway speeds, so I’d check that out .

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[xmac911]

The whine similar to a jet landing and taxiing on the runway is mostly on deceleration, and definitely pinion bearing , the tone at 60 mph + is a bit different , but could very well be that as well.    But know that some old tires can also “ howl “ at highway speeds, so I’d check that out .

 

Thanks, the tires are new pilot cup sports, with only a few hundred miles but will check. Small world, I fly out of San Carlos regularly. 

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[ds968]

 

Thanks, the tires are new pilot cup sports, with only a few hundred miles but will check. Small world, I fly out of San Carlos regularly. 

Michelin  Pilots are very quiet , even in their old age. ( that’s what I have on all my cars ) , so it’s probably not that .. pinion bearing seems more and more to be the culprit .

I lived in San Carlos for 40+ years , but moved to SoCal a couple of years ago .. San Juan Capistrano , although it doesn’t have an airport of its own .  -_-

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[tejon007]

There are 4(?) Bearings inside the torque tube. So, it could be one of those. Maybe some careful stethoscope listening while driving 62MPH? You might be able to make contact with the TT by the shifter with some disassembly...



When you balance shaft belts are 180 out, you should be able to notice the vibration and it tends to get worse with more RPMs.



Best wishes for a successful fix!

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[xmac911]

I crawled underneath and to my horror, I saw remnants of foil tape and a slot in the torque tube. I thought 1994's and up had no slot cut in the torque tube housing??

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[xmac911]

There are 4(?) Bearings inside the torque tube. So, it could be one of those. Maybe some careful stethoscope listening while driving 62MPH? You might be able to make contact with the TT by the shifter with some disassembly...



When you balance shaft belts are 180 out, you should be able to notice the vibration and it tends to get worse with more RPMs.



Best wishes for a successful fix!

 

Thanks. There was definitely significant vibration at higher rpms's. 

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[Inkedupfatboy]

Didn't the pinion bearing issue happen at low mileages? I thought it was an assembly issue with the robot putting things together with the incorrect preload? Mine went at 44K before I owned the car and I bought it when it wasn't running and that was my first gift after we did get it moving again. Cost me $2700 for a rebuild with a 2 year warranty. We are 11 years and 6 thousand miles (right, I don't drive it much, it still only has 50K on the clock) into ownership and no issues. Everyone describes it as a jet engine sound, but I didn't feel that. It's just a loud assed noise that fills the car and you can't hear anything else. Don't call a Porsche garage, even Brumos didn't want to work on it.

Find a good independent tranny shop - mine works on everything from Ferrari's on down but he's in FL. I was glad I found him because my only other two options were to ship it to CA, or swap in a used one and not have the numbers match....

Good luck with your new toy & stop driving with headphones on! it's not safe, LoL

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[xmac911]

Didn't the pinion bearing issue happen at low mileages? I thought it was an assembly issue with the robot putting things together with the incorrect preload? Mine went at 44K before I owned the car and I bought it when it wasn't running and that was my first gift after we did get it moving again. Cost me $2700 for a rebuild with a 2 year warranty. We are 11 years and 6 thousand miles (right, I don't drive it much, it still only has 50K on the clock) into ownership and no issues. Everyone describes it as a jet engine sound, but I didn't feel that. It's just a loud assed noise that fills the car and you can't hear anything else. Don't call a Porsche garage, even Brumos didn't want to work on it.

Find a good independent tranny shop - mine works on everything from Ferrari's on down but he's in FL. I was glad I found him because my only other two options were to ship it to CA, or swap in a used one and not have the numbers match....

Good luck with your new toy & stop driving with headphones on! it's not safe, LoL

 

 

Great way to put it, that is what it sounds like - "loud assed noise that fills the car." Without noise cancelling earbuds in, I would not be able to hear a thing. Luckily that was just for the drive to my garage. It is currently on jack stands getting some much needed attention in many areas.  What shop in CA were you considering doing the rebuild? 

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[ds968]

Ken’s Sportech ( in Saratoga or Campbell or somewhere in the South Bay ) did mine but that was more than 25 years ago , so I have  no cue if they’re still in business , or moved , or whatnot ..   back then it cost about $ 2,000 , if I recall correctly .. 

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[xmac911]

Ken’s Sportech ( in Saratoga or Campbell or somewhere in the South Bay ) did mine but that was more than 25 years ago , so I have  no cue if they’re still in business , or moved , or whatnot ..   back then it cost about $ 2,000 , if I recall correctly .. 

 

 

Thanks! It looks like it is now just "Sportech" in Campbell. I'll check them out. 

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[lbpesq]

I’ve been using BauerWerks in Oakland for over 10 years.   The first time I walked in they had several 968s in the shop.  Brian and his dad are nice guys who really know the 968 and have reasonable prices (this is a Porsche!)

 

Bill, tgo

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[paulzebo]

Don't overlook the rear wheel bearings. My TIP had the same noise and that's what it turned out to be.

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[xmac911]

I’ve been using BauerWerks in Oakland for over 10 years.   The first time I walked in they had several 968s in the shop.  Brian and his dad are nice guys who really know the 968 and have reasonable prices (this is a Porsche!)

 

Bill, tgo

 

Great option. Thanks!

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