924Board.org

[cgalyon]

Ever since I picked up this car (only a couple of weeks ago) I've heard this sort of scraping sound. Originally it sounded like it was coming from the back of the car and I thought it might be gunked up brake calipers holding the pads down on the rotor. Since I also had a squishy brake pedal, that just furthered my suspicions that the brakes needed work. However, I've been experimenting with the noise some more since getting my car back from the shop and now I believe it might be connected to the clutch. Here's the gist:

When I drive my car and get to a cruising speed, I begin to let off the gas a bit. If I let off the gas without pressing in on the clutch, then there's a sort of scraping noise (that now I believe to be emanating more from the front passenger side of the car). If I apply gas, the noise seems to vanish though (that's what seems really weird to me). If I press the clutch in, then the noise vanishes as well. As soon as I let off the clutch again, and if I'm not really applying gas (cruising), then I hear the scraping again. I notice it most clearly in 5th, but believe it's present in all of the gears if I'm in gear and not applying gas. Any ideas?

Thanks in advance!
_________________
1988 924S Navy Blue - Phone Dials

[cgalyon]

Digging around a bit, I found this:

"9.1 When I release my clutch in neutral, I hear noises, is this bad?

Not usually. The transmission has several shafts that the gears move back and forth on. On the end of one of these shafts is the 5th "floating" gear. This gear rattles back and forth because it has a larger tolerance than the others. Porsche apparently stopped all warranty repairs for this noise because there is no real repair - the larger tolerance is normal. The noise is particularly evident because it vibrates the input shaft which is connected to the torque tube that runs up the middle of your car. This creates a megaphone type effect that amplifies the noise."

So maybe, if I'm lucky and all is well, that's all it is... I'm going to see if I can find some kind of recording device to record the sounds it makes and post a link to it for help with diagnosing the problem. It may be nothing to be concerned about, but I figure you guys will know.
_________________
1988 924S Navy Blue - Phone Dials

[Rasta Monsta]

Lay under it while its running to get a better read on where it is coming from. . .the section you quoted would refer to a sound coming from the gearbox in the rear of the car. Could be a throwout bearing going dry.
_________________
Toofah King Bad

• WeiBe (1987 924S 2.5t) - 931 S3

[bcblase]

I have changed the transmission in my car twice, and the torque tube once, (with old used parts) trying to get rid of that same noise, but to no avail. I have been told that only a newly re-built tranny and torque tube will solve the noise issues.

This place has good rebuilt parts, but still too rich for my pocketbook right now:

www.944ecology.com

Re-built tranny: $1,500
Re-built torque tube: $500

I have just gotten used to the noises, and consider everthing Ok as long as the noises don't change, or get louder.
_________________
1987 Porsche 924S - track toy
1986 Mercedes 190E 2.3-16v - autocross
2007 F-150 5.4L Lariat Supercrew - tow beast
1994 Volvo 850 Race Wagon - 24 Hours of Lemons Car
2001 BMW 325xi - daily driver

[cgalyon]

Rasta, the noise seems to only appear when I'm in gear. So when I start it up and let it idle for a bit, there's no noise. Now I suppose I could get under a moving car, but...

In response to bcblase, from one source I read, it does seem like it might just be the normal car noise (though I don't recall my 944 ever making that noise). Hopefully it is, but I'll try to get a recording today if I can and will link it to this thread.
_________________
1988 924S Navy Blue - Phone Dials

[cgalyon]

Well I've completely failed at getting that recording. I accidentally left the device I was going to use for recording at the office. I'll have to see if there's some other way to get the recording... Hopefully the audio quality won't suck too badly!
_________________
1988 924S Navy Blue - Phone Dials

[bcblase]

The noise I was having problems with was similar to your car, except that when coasting in neutral, clutch in or out, the noise was coming loudest whenever the rear wheels were in motion, so I knew it was the tranny. I had a brand new clutch, so I knew it was not likely the problem.

Engaging the clutch stops the driveshaft and tranny pinion gear from spinning and the noise should go away when the car is not moving.

When moving, the application of gas/power to the tranny can make the sound go away, but when coasting (no power applied) the noise is louder, right?

Sounds like you have the same pinion gear/bearing problem I had - not fatal but really annoying.

BC
_________________
1987 Porsche 924S - track toy
1986 Mercedes 190E 2.3-16v - autocross
2007 F-150 5.4L Lariat Supercrew - tow beast
1994 Volvo 850 Race Wagon - 24 Hours of Lemons Car
2001 BMW 325xi - daily driver

[cgalyon]

It does sound like it's probably the same thing. How much did it cost for you to fix yours? I'll probably need to wait a while on that problem depending on the cost.
_________________
1988 924S Navy Blue - Phone Dials

[bcblase]

I bought an older tranny from an '84 944 - "QM" type with short 5th gear, for $300 on eBay, but it cost $100 to ship it from the mid-West, so it ended up costing like $400.

I bought my old original QK tranny back from JoeC, so now I have three extra trannys:

1. My original 924S "QK" type with tall 5th gear, 3rd gear synchro is rough
2. JoeC's 924S "QK" tranny - pinion gear howls like a banshee - needs to be rebuilt
3. "5P" tranny w/oil cooler from a 951, gear ratios too high for 924S

FYI - the "QM" tranny is still pretty noisey - it makes more noise when you get on the gas, instead of off of it.

I should have just dropped $1500 on a fully rebuilt "5Y" and $500 on fully rebuilt torque tube.

BC
_________________
1987 Porsche 924S - track toy
1986 Mercedes 190E 2.3-16v - autocross
2007 F-150 5.4L Lariat Supercrew - tow beast
1994 Volvo 850 Race Wagon - 24 Hours of Lemons Car
2001 BMW 325xi - daily driver

[cgalyon]

Finally managed to make a recording... and if you listen I apologize for the painful popping and rustling (the recorder's case made lots of noise); I recommend skipping to about halfway through to get a much cleaner, purer sound of the car itself.

Wow, and I forgot to link the recording... sorry!

http://neopong.com/download/080521_01.wav
_________________
1988 924S Navy Blue - Phone Dials