968Forums.com
Could this be part of my transaxle noise? - Printable Version

+- 968Forums.com (https://968forums.com/forum)
+-- Forum: FIXING MY BABY - OEM REPAIRS (https://968forums.com/forum/fixing-my-baby-oem-repairs)
+--- Forum: TRIAGE AND DIAGNOSING YOUR PROBLEM (https://968forums.com/forum/triage-and-diagnosing-your-problem)
+---- Forum: What is that noise? (https://968forums.com/forum/what-is-that-noise)
+---- Thread: Could this be part of my transaxle noise? (/could-this-be-part-of-my-transaxle-noise.html)


Could this be part of my transaxle noise? - Cloud9...68 - 08-31-2013

Several weeks ago, I had a false alarm, thinking the noise I was hearing from the rear of my car was the dreaded pinion bearing, but I was assured by someone familiar with these transaxles that the sound coming from the back definitely isn't pinion bearing noise - just general transaxle gear noise reverberating inside a cabin with several of its sound-absorbing panels removed, and a half cage welded to the chassis.



But the sound still bugs me, and seems to be louder and more intrusive than it should be (although of course I don't notice it at the track). And if anything, it sounds like a lot of it could be coming from the linkage; it actually sounds a little like the shifter buzz from my aftermarket shifter, but coming from the rear of the car. So I got under there and poked around, and found that the bushing shown in the picture is a little loose on its fitting, enough that it rattles as I move it around with my hand. Is it normal for this bushing to have a noticeable amount of play?



   



Also, speaking of linkage noise, is it likely that replacing my lightweight shift knob with an OEM 968 knob will quiet things down throughout the linkage, even in back? This may be a reach - just looking for possibilities. Thanks.

Could this be part of my transaxle noise? - MB968 - 09-01-2013

Is that the link that is part of the shifter mechanism at the tranny? Not that familiar with the car in that area, but helped EK fix a broken short shifter and that looks something like the part I remember. If so I don't think there should be any looseness in the ball/socket ends on that part. You should be able to rotate the part on the ball ends, but should not have any radial slop.



And to answer your question, it could be your noise or buzz. Just some thoughts on how to help identify it or not as the issue. Is there a way to put a bungie from the part to something else in the area to provide some side pull (eliminating the slop/ability to rattle) just as a temporary test. Or, wrap some foam pipe insulation around it all the way to the ends so it can't rattle, or ??? Then you could test drive it and see if the noise is eliminated or at least significantly changed by what you've done.

Could this be part of my transaxle noise? - AJG - 09-01-2013

Try replacing the bellows, that can perish over time.

Could this be part of my transaxle noise? - Cloud9...68 - 09-01-2013

MB,



Yes, the ball/socket I'm referring to is the shift linkage at the tranny. I like your idea about temporarily "stabilizing" it to to prevent the socket from moving radially against the ball - I'll see if I can rig something up.



AJG,



What is this bellows you're referring to?



Thanks.

Could this be part of my transaxle noise? - flash - 09-01-2013

i use a rubber grommet under the ball head to "absorb" the buzz. by the way, the noise it makes is a rattly buzz. it is not a bearing sound at all.

Could this be part of my transaxle noise? - AJG - 09-01-2013

There is a rubber piece at the tranny end of the gear linkage, I think its has a cushion effect and if worn would cause looseness. Its part# 477 711 159 B.

Could this be part of my transaxle noise? - Cloud9...68 - 09-01-2013

Thanks for the info and the tips. The noise I'm hearing is actually more of a buzz than a bearing sound (with the caveat that I don't know what a worn pinion bearing actually sounds like, since my car apparently doesn't have that, based on the input from the guy I took it to). I realize the car will never be quiet, and that with the changes I've made, I'm going to hear noises I never heard before - I just want to track down noises that shouldn't be there.

Could this be part of my transaxle noise? - flash - 09-01-2013

the pinion bearing is a constant sound, varying with rotational speed.



the link at the rear is more of an rpm specific buzz. it will come and go, dependent on harmonics. mine was most prevalent at about 2300 rpm, which is coincidentally where the single mass flywheel makes everything in the rear buzz. no fixing that one though. with everything removed inside the car, that should be pretty darned loud and annoying.

Could this be part of my transaxle noise? - AJG - 09-01-2013

Had a look at the linkage diagram to refresh my memory. The bellows is on the end of the intermediate shaft. These do perish and its looks like an easy fix.

Could this be part of my transaxle noise? - Cloud9...68 - 09-01-2013

Next time I have the car up in the air, I'll have a look at the intermediate shaft and at the bellows. The sound is definitely constant, not rpm-specific (other than the rattle from the SMF). Not a huge issue, as I expected compromises given the car's configuration. The noise is actually more annoying that the ride quality, which isn't what I expected. It just has a buzzy, linkage-sounding quality to it.

Could this be part of my transaxle noise? - AJG - 09-01-2013

The intermediate shaft, item assy #21 on the Porsche parts list for foot pedal and lever assy's has two shafts passing through at right angles they could do with some WD40. The bellows is attached in this area. Its as cheap as chips to replace.

Could this be part of my transaxle noise? - flash - 09-02-2013

use a lube like tri-flow, and not WD40, which is mostly solvent. grease is even better

Could this be part of my transaxle noise? - AJG - 09-02-2013

The WD will help get rid of any crud, a blow with compressed air might not hurt, but yeah grease it up if you will. Remember its all exposed under there and grease will attract more crap.

Could this be part of my transaxle noise? - flash - 09-02-2013

it seems to stay surprisingly clean in that area though, so i'm not sure grease would be a problem.



i use WD-40. i just don't use it as a lube. it's great for cleaning things up and breaking things loose a bit. it just dries up after that, and doesn't leave much lube that sticks around for long. lol - maybe that's by design, so that you have to keep applying it, and therefore have to keep buying more.

Could this be part of my transaxle noise? - Tom030 - 09-02-2013

How's that saying go,If it sticks and shouldn't WD 40, if it doesn't stick and should, duct tape.

Could this be part of my transaxle noise? - MB968 - 09-02-2013

The WD in WD40 stands for Water Displacement which was it's original intent when developed. As had been said, it's good for a variety of things, but as a lubricant, it has very low/poor properties.

Could this be part of my transaxle noise? - Cloud9...68 - 09-03-2013

So why is it so effective at quieting squeaky door hinges?

Could this be part of my transaxle noise? - flash - 09-03-2013

it dissolves the rust and leaves "clean" material. new hinges don't squeak either.

Could this be part of my transaxle noise? - MB968 - 09-03-2013

Better to have some limited lube capabilities than none, and it will wet/flow/wick into tight joints like hinges. It won't dissolve the rust, but it might flush it away some. Best if you need lubrication, to use tri-flow, or a spray white lithium, or the like depending on what you are trying to lube. Long term you'll have to service it a lot less.

Could this be part of my transaxle noise? - flash - 09-03-2013

the solvent seems to break the rust away and indeed flush it away suspended in a liquid form. by definition, that is "dissolve", which is to cause a solid to be incorporated into a liquid. not sure what else to call what it does.