thomasmryan

tn side. I love it here. so many fun roads to choose from.

modular bearings are actually two rows of bearing. during the process of torqueing down the axle nut, you are pinching the two halves together as the stub axle acts as the bolt. if the wheel is on the ground, it can load the assembly and you really don't get an accurate torque. i set the drive extension on a jack stand or scissor jack to keep level.

our tensioner, like a shock, can get air on the wrong side of things. it's best to run the shocks through their motion of travel a few times in the vertical prior to installing them to purge the air. the tensioner is treated the same because its kinda a shock with a spring added

Karrera Coupe

Thanks Thomas. I have so much to learn!

Yogii

So after all of this I am still not much wiser as to what is causing the droning sound. I am now starting to wonder whether I am overly sensitive to this droning sound and that I should just try to ignore it.

would really like to be able to compare it to another 968 but unfortunately I do not know any local 968 owners that I can go and compare my car with.

Do the experienced 968 owners out there have any other ideas for me?

Thanks in advance.[/QUOTE]

Comparing your car, particularly if it is new to you, with a known well kept sibling is a great thing. When I first got my car, i was worried about the 2 and 3 rd gear sycros after having a known 968 enthusiast confirmed Nothing to Worry About, I felt much better. Thanks Arash!

-Y

Karrera Coupe

Yogii if I can find another 968 enthusiast locally it will be very helpful to make comparisons and get expert advice. There is a BAT contributor that goes by the name Gulf-Porsche 21 that seems to very knowledgeable on our transaxle cars (924s, 944s, and 968s). I gathered that he is based right here in my home town Charlotte. But I have not found a way in which to reach out to him.

Yogii

Are you a PCA member? They can help.
Have you tried PMing Gulf-Porsche 21?

-Y

Karrera Coupe

Yogii I don't k know that I can PM a contributor on BAT unless he is the seller on an active auction. If you know how to do so please let me know.

I am a PCA member but I am not active. I only read the magazine and use the website. Maybe I should start attending some of the local PCA events to find other 968 enthusiasts. That is if there are any here in our region.

Karrera Coupe

After replacing the CV joint boot that sits above the exhaust muffler and repacking the CV joint itself with grease I took my car for a test drive this afternoon. Unfortunately the droning sound is as audible as ever.
I am now considering replacing the two rear Firestone Firehawk Indy 500 rear tires that I installed at the beginning of January, which was also when I became aware of the droning noise (after fixing a few other problems including misaligned balance shafts). I bought the two Firestone tires as the Conti's that I wanted to install was unavailable at that the time and my car's annual inspection was due. The Conti's are now available on Tire Rack.
I reckon that even if installing the new Conti's does not prove to fix the droning noise, I can just use them up and then re-install the current Firestones? Does that make sense considering the immediate cost of replacing 2 hardly used tires?

Charlie

Hope tires will solve the problem, let us know.

Karrera Coupe

Will do Charlie. I am going to have some bumps and bruises on the body work repaired before I tackle the tires. Probably another two or so months before I get to them.

User 41221

Did you consider the torque tube? With that amount of mileage, they tend to get louder.

Karrera Coupe

I have thought of the torque tube. Whether I have thought about it enough is an open question.
When driving in the speed range in which the droning is at its loudest, there is no change in the sound when I engage the clutch. My understanding is that the torque tube will start turning less fast when no longer driven through the clutch. There is also no change in the sound when I engage the clutch and take the transmission out of gear. Only the speed at which the wheels are rolling seems to affect the droning sound.
When I had my car on a lift with the engine running and transmission engaged, in other words the rear wheels were being driven (not at the speed at which the droning starts which is around 40 mph) we listened to various components with a mechanics stethoscope. Although we did not have anything with which to compare the sound coming from the turning torque tube, it did not sound to me and to the technicians at hand in the shop, as if there was anything amiss with the torque tube.
Problems is that nothing else seemed to be causing the droning sound either.
I sometimes get the impression that the level of the droning sound changes on different pavements. On some road surfaces it seems to be much more noticeable and on others hardly at all. If this is true (I am not sure yet) it probably points the finger at the two new rear tires.
Thanks for your interest.

Madridcab

Just quickly read through this, is this not the typical symptoms of gearbox bearing failure, known common issue on these cars?

Karrera Coupe

Thanks Madridcab for your question/input. I assume you are referring to the transmission pinion bearing failure issue.
I just reran a google search I tried before and got the following link: http://www.968forums.com/topic/4024-pinion-bearing/
I was very excited to see links to recordings of a car with a failing transmission pinion bearing failing. Unfortunately the thread is so old that the I links to the audio files are now longer valid.I will post on that thread to try and find somebody who may have retained the audio files themselves.

I have considered the transmission pinion bearing failure as a potential source of my droning noise. I was advised to test whether it is by driving in the speed band when the droning noise is present and then to engage the clutch and to take the transmission out of gear. and to listen for a change in the droning noise. I did so a couple of times but there was no change in the droning noise when following this little procedure.

I think the idea is that with the clutch engaged the torque tube shaft stops driving power into the transmission and with the transmission in neutral (out of gear) the wheels will also stop turning the transmission gears.So with nothing turning or at least putting power into the transmission it should stop droning if that was the problem to start with.
This is all above my pay grade. I am just trying to repeat what I have read/heard. Does it make sense or did I get the reasoning and test completely wrong?
Thanks again.

LTCMontana

A few thoughts...
1) Any 944 (late offset) wheels will fit your car. Recommend posting over in the 944 section to see if there are some locals in your area who would be willing to swap wheels/tires with you in order to trouble shoot. The 944/968 crowd is generally over friendly and I am confident you'll find someone in Charlotte.
2) Reach out via email/phone to your local PCA Pres/Vice. Most know the clicks well and can steer you to someone with a similar car.
3) Vibrations/droning can transfer through all kinds of things so you might be looking in the wrong area. Thoroughly check the exhaust system to make sure all brackets are in place and make sure none of the pipes are touching any other surface on the car. You mentioned a replacement engine and trans so some things may be out of place. I have a '14 Audi A8 with the 4.0tt. It had a very annoying vibration at a particular RPM. Everything pointed to a transmission problem because it would happen right as the car needed to shift to the next higher gear. Turns out, the downpipes were resonating at a specific freq at that RPM. Audi replaced them and noise went away.

Karrera Coupe

Thanks LTCMontana for your suggestions. I have not thought of reaching out to local 944 owners via the 944 forum. I will do so in the next month or so - i.e. after the needed body work are done at the end of this month. I am a PCA member - but only for the magazine. I don't participate in their get togethers. A while ago I reached out to the technical representatives per their contact details in our local PCA month mag (Tobacco Roads) but onily received a reply from one of the three guys listed and his response was that he moved back to Chicago about 3 years ago!
If I don't have any luck reaching out to local 944 Renllisters, I will give our Regional PCA president or vice a call.
I have had a good luck at the excaust and it all looked in order. A local indy shop here just south of Charlotte's owner is knowledgeable about 944s. We had it up on one of his lift with rear wheels rolling and using the mechanical stethoscope but wasn't able to identify anything. The engine and transmission replacement was done a long time ago by a previous owner. It has never been a quiet car but during my first three years of ownership I never noticed this particular droning sound. I only noticed it after replacing the rear tires. That's why I want to eliminate the new tires ast possible cause before I spend more effort trying to solve.
Thanks again for your advice,