Help with DIY and Diagnosis - possible prop shaft problem?
03-23-2006, 05:38 AM
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Help with DIY and Diagnosis - possible prop shaft problem?
Hello everyone:
Lately, I've been having an unusual noise and would like to get some opinions as to wether I'm on the right track or not. My vehicle is a 2001 A4 1.8t quattro, manual tranny, with about 100k miles.
About a week ago, I started hearing a sort of clicking or tapping noise from under the car, under gentle acceleration at low speeds. It almost sounded like something (rope or wire) was wrapped around one of the driveshafts and was hitting the body of the car. It seems to be related to vehicle speed, and doesn't seem to be related to engine speed, clutch engagement, or being in a certain gear.
The noise came and went for a few days, but over the last day or two it's gotten quite loud, and it's now happening at a wider range of speeds (right up to highway speeds sometimes) and independant of accelerating. I can't really tell where it's coming from, but it definitely sounds like under the car towards the front somewhere. One other interesting point is that it seemed to go away under braking yesterday.
At first, I figured it was one of the CV joints on one of the front halfshafts. I thought this because the noise sounds similar to noises I've heard on FWD cars when a front outer CV fails - a sort of rhythmic ticking or clicking noise, though in those cases the noise seemed to happen at low speed when doing tight turns. But, all 4 of the CV's on the front halfshafts look totally fine (boots do, at least) and there doesn't seem to be any play up there.
I started searching on here and saw a bunch of threads where people were complaining of center support bearing or CV problems associated with the prop shaft, so now I'm wondering if that's my problem as well.
Anyone have any ideas? Any tips for diagnosing or repairing center driveshaft problems? I looked over the prop shaft troubleshooting guide at blau and none of the descriptions there seem to exactly fit my problem. This sounds like a really silly way to describe the noise, but it's the best I can come up with - it sounds like someone's under the car with a small tool, beating it back and forth really fast against something in the driveline. There aren't any lurches, hesitations, bumps, vibrations, or any other problems - the car drives and feels totally fine, except for this noise.
What tools do I need to get it off? In a quick look under the car, it looked like the bolts in the CV joint on the front of the shaft were hex (i.e. allen) head, anyone know the size? If I have to remove the whole shaft, does the center bearing just unbolt from the car as well? Anyone know the sizes of those fasteners? Once it's out, if I need to just replace a CV joint, are they easy to get off the shaft?
Anyone know of a prop shaft removal DIY walkthrough somewhere on the 'net?
Thanks everyone in advance!
-Nate
2001 A4tqms
Lately, I've been having an unusual noise and would like to get some opinions as to wether I'm on the right track or not. My vehicle is a 2001 A4 1.8t quattro, manual tranny, with about 100k miles.
About a week ago, I started hearing a sort of clicking or tapping noise from under the car, under gentle acceleration at low speeds. It almost sounded like something (rope or wire) was wrapped around one of the driveshafts and was hitting the body of the car. It seems to be related to vehicle speed, and doesn't seem to be related to engine speed, clutch engagement, or being in a certain gear.
The noise came and went for a few days, but over the last day or two it's gotten quite loud, and it's now happening at a wider range of speeds (right up to highway speeds sometimes) and independant of accelerating. I can't really tell where it's coming from, but it definitely sounds like under the car towards the front somewhere. One other interesting point is that it seemed to go away under braking yesterday.
At first, I figured it was one of the CV joints on one of the front halfshafts. I thought this because the noise sounds similar to noises I've heard on FWD cars when a front outer CV fails - a sort of rhythmic ticking or clicking noise, though in those cases the noise seemed to happen at low speed when doing tight turns. But, all 4 of the CV's on the front halfshafts look totally fine (boots do, at least) and there doesn't seem to be any play up there.
I started searching on here and saw a bunch of threads where people were complaining of center support bearing or CV problems associated with the prop shaft, so now I'm wondering if that's my problem as well.
Anyone have any ideas? Any tips for diagnosing or repairing center driveshaft problems? I looked over the prop shaft troubleshooting guide at blau and none of the descriptions there seem to exactly fit my problem. This sounds like a really silly way to describe the noise, but it's the best I can come up with - it sounds like someone's under the car with a small tool, beating it back and forth really fast against something in the driveline. There aren't any lurches, hesitations, bumps, vibrations, or any other problems - the car drives and feels totally fine, except for this noise.
What tools do I need to get it off? In a quick look under the car, it looked like the bolts in the CV joint on the front of the shaft were hex (i.e. allen) head, anyone know the size? If I have to remove the whole shaft, does the center bearing just unbolt from the car as well? Anyone know the sizes of those fasteners? Once it's out, if I need to just replace a CV joint, are they easy to get off the shaft?
Anyone know of a prop shaft removal DIY walkthrough somewhere on the 'net?
Thanks everyone in advance!
-Nate
2001 A4tqms
03-23-2006, 05:48 AM
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Grab onto it and see if there is play in it. --->
It's a pain to get out. Remove exhaust, heat shields etc.
Last time i checked you couldn't replace just the CV's etc. You had to buy a whole shaft from the stealer ($8-900!!!)... maybe that's changed. With that said i have a good used one for parts if you need it that *maybe* I'd part with.......was keeping it for my use if i needed it.
It sounds like you have another issue as a bad CV/center bearing in that prop-shaft will show up as a vibration not a clicking as the cv's don't angle setting up a "bind" and clicking. If they were bad enough to click they would be vibrating BAD and would feel very loose to the "grab onto it and shake" test.
Almost sounds like maybe a heat shield or something is hitting the prop-shaft? Could possibly even be as simple as a brake pad etc. I doubt it's the shaft CV's, the center bearing is more possible, but very unlikely.
Doug.
Last time i checked you couldn't replace just the CV's etc. You had to buy a whole shaft from the stealer ($8-900!!!)... maybe that's changed. With that said i have a good used one for parts if you need it that *maybe* I'd part with.......was keeping it for my use if i needed it.
It sounds like you have another issue as a bad CV/center bearing in that prop-shaft will show up as a vibration not a clicking as the cv's don't angle setting up a "bind" and clicking. If they were bad enough to click they would be vibrating BAD and would feel very loose to the "grab onto it and shake" test.
Almost sounds like maybe a heat shield or something is hitting the prop-shaft? Could possibly even be as simple as a brake pad etc. I doubt it's the shaft CV's, the center bearing is more possible, but very unlikely.
Doug.
03-23-2006, 07:02 AM
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Some play. . .
Last night I crawled under the car for a minute. I grabbed the propshaft and it didn't seem like it was ultra-sloppy. I don't recall there being any wiggle-around sloppiness, but I could rotate it quite a bit in either direction - there seemed to be some sloppiness in that manner (gotta love my ultra-technical terms, huh?)
Anyone have thoughts if it's not something related to the propshaft?
-Nate
2001 A4tqms
Anyone have thoughts if it's not something related to the propshaft?
-Nate
2001 A4tqms
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