Joined
·
4,104 Posts
Some of you know that I got my driveshaft replaced this week by Chevrolet under warranty, to eliminate the "tick" sound that was occurring due to windup and then release of the aluminum drievshaft when starting from a dead stop, and sometimes when the automatic transmission shifted gears.
Well, there's good knews and bad news!
The good news is that the tick sound is gone.
The bad news is that it has been replaced by a much more irritating and persistent hollow, resonant sound that shows up at high city speeds and becomes more pronounced at highway speed!
I didn't realize what had happened at first as a result of this driveshaft swap, and it's embarassingly funny.
Basically, I picked the SSR up from the dealership and drove pretty much immediately, with the sound system on (significant - see below), to a high performance shop where I had an appointment to do something unrelated: change the rear axle ring and pinion from the stock 3.73 to 4.56, as described in another of my postings. It never occured to me that anthing was amiss, especially since, because of route and traffic, I did almost all the driving at city speeds.
I pciked the SSR up again last night with the new axle ratio ALSO installed, and did something I don't normally do: I drove WITHOUT the sound system on. I normally like to play music all the time in the SSR these days, because I am away from home in Atlanta on a contract assignment, living in a hotel, and have NO other sound system! BUt, after picking up the SSR from the high performance shop, I wanted to specifically listen to see if the 4.56 gears would be noticeably louder than the 3.73 had been, so I turned the sound system OFF, AND the blower fan to the "1" setting..
Yeah, you guessed it. I heard this sound that I described above, and, because I thought it had not been there before, assumed it was due to the 4.56 gears! I called the shop, and Lamar, the owner, told me that his son Rob, who did the gear install, had roadtested the SSR before I picked it up, commented on the "driveshaft sound", checked to confirm it was coming from the dirveshaft and not the rearend, and unfortunatey left for the day before I arrived to pick the SSR up, so couldn't tell me. When Lamar told me what Rob had found, we all got really curious, as Lamar himself owns an SSR (an early 03, not an 04 as I had originally thought). Rob and Lamar invited me to bring the SSR in again today and they would put it on a lift and run it!
Yes, again you can probably guess what we found with the SSR running on a lift with the wheels above ground and the drievtrain turning like on the road. The differential was quiet as a church mouse (Rob HAS done many of them and knows how to do them well). But that driveshaft was a different story.
First, even before running it, Lamar, who remember has an 03 SSR AND is a skilled auto tuner and builder, noted that this new driveshaft:
- Has a MUCH larger diameter than the one in his SSR (no ruler with me, but looked like maybe 5 inches diameter in that central section!)
- Appears to have no sound deadening material in it (it rings like a bell when you flick it with your finger!)
- Is VERY light guage aluminum, has a sort of rubber doughnut at the front to try to dampen noise
- And most significantly, has WAY too much physical "play" in the coupling to the bushing inside the transmission. We were easily able to defect the front of the driveshaft away from center with very moderate hand pressure. There is literally visible play in the coupling with the transmission.
Once we ran it, we could clearly hear that the commotion was coming from the front end of the driveshaft.
Then, just to be sure, Lamar himself test drove my SSR, and confirmed his opinion.
He and Rob told me that they have also encountered this noise on Corvettes, which also use a very light and resonant driveshaft that operates at high rotational speed because in a Corvette, the transmission is at the rear axle. When it's bad, they send the driveshaft out to a local driveline place that installs sound deadener.
I don't think there is any chance that the Chev dealer mechanic installed the new drivesahft incorrectly somehow, as the driveshaft is PURELY the driveshaft (the u-joints are NOT part of what was replaced), and it fastens to the u-joints with simple bolts (4 bolts total I think). It's also not bent or unbalanced, because there really is no vibration to speak of - it`s just noise (which a scientist will tell us IS the result of a high frequency virbation). I think there are 3 possibilities:
1. The factory forgot to put sound deadener into this specific driveshaft.
2. The frontend of this specific driveshaft is somehow out of tolerance (i.e. it's not supposed to have the large amount of play that it does have)
3. The new driveshaft design gets rid of the "tink" (which was mildly annoying, and caused all my mechanic friends to incorrectly say "you need new u-joints"), and replaces it with an anoying hollow resonant sound that is frankly more annoying than the tink ever was!
I called my Chevrolet dealer and told the service rep that I don't like this new driveshaft, and either want a new one that does not make the noise, OR I want to go back to my old one (tick is better than the noise). He is checking to see if they still have my old one!
The dealer invted me to come in Monday to continue "The driveshaft story"!
I'll let you guys know what happens next.
Isn't owning an SSR fun?
Jim G
Well, there's good knews and bad news!
The good news is that the tick sound is gone.
The bad news is that it has been replaced by a much more irritating and persistent hollow, resonant sound that shows up at high city speeds and becomes more pronounced at highway speed!
I didn't realize what had happened at first as a result of this driveshaft swap, and it's embarassingly funny.
Basically, I picked the SSR up from the dealership and drove pretty much immediately, with the sound system on (significant - see below), to a high performance shop where I had an appointment to do something unrelated: change the rear axle ring and pinion from the stock 3.73 to 4.56, as described in another of my postings. It never occured to me that anthing was amiss, especially since, because of route and traffic, I did almost all the driving at city speeds.
I pciked the SSR up again last night with the new axle ratio ALSO installed, and did something I don't normally do: I drove WITHOUT the sound system on. I normally like to play music all the time in the SSR these days, because I am away from home in Atlanta on a contract assignment, living in a hotel, and have NO other sound system! BUt, after picking up the SSR from the high performance shop, I wanted to specifically listen to see if the 4.56 gears would be noticeably louder than the 3.73 had been, so I turned the sound system OFF, AND the blower fan to the "1" setting..
Yeah, you guessed it. I heard this sound that I described above, and, because I thought it had not been there before, assumed it was due to the 4.56 gears! I called the shop, and Lamar, the owner, told me that his son Rob, who did the gear install, had roadtested the SSR before I picked it up, commented on the "driveshaft sound", checked to confirm it was coming from the dirveshaft and not the rearend, and unfortunatey left for the day before I arrived to pick the SSR up, so couldn't tell me. When Lamar told me what Rob had found, we all got really curious, as Lamar himself owns an SSR (an early 03, not an 04 as I had originally thought). Rob and Lamar invited me to bring the SSR in again today and they would put it on a lift and run it!
Yes, again you can probably guess what we found with the SSR running on a lift with the wheels above ground and the drievtrain turning like on the road. The differential was quiet as a church mouse (Rob HAS done many of them and knows how to do them well). But that driveshaft was a different story.
First, even before running it, Lamar, who remember has an 03 SSR AND is a skilled auto tuner and builder, noted that this new driveshaft:
- Has a MUCH larger diameter than the one in his SSR (no ruler with me, but looked like maybe 5 inches diameter in that central section!)
- Appears to have no sound deadening material in it (it rings like a bell when you flick it with your finger!)
- Is VERY light guage aluminum, has a sort of rubber doughnut at the front to try to dampen noise
- And most significantly, has WAY too much physical "play" in the coupling to the bushing inside the transmission. We were easily able to defect the front of the driveshaft away from center with very moderate hand pressure. There is literally visible play in the coupling with the transmission.
Once we ran it, we could clearly hear that the commotion was coming from the front end of the driveshaft.
Then, just to be sure, Lamar himself test drove my SSR, and confirmed his opinion.
He and Rob told me that they have also encountered this noise on Corvettes, which also use a very light and resonant driveshaft that operates at high rotational speed because in a Corvette, the transmission is at the rear axle. When it's bad, they send the driveshaft out to a local driveline place that installs sound deadener.
I don't think there is any chance that the Chev dealer mechanic installed the new drivesahft incorrectly somehow, as the driveshaft is PURELY the driveshaft (the u-joints are NOT part of what was replaced), and it fastens to the u-joints with simple bolts (4 bolts total I think). It's also not bent or unbalanced, because there really is no vibration to speak of - it`s just noise (which a scientist will tell us IS the result of a high frequency virbation). I think there are 3 possibilities:
1. The factory forgot to put sound deadener into this specific driveshaft.
2. The frontend of this specific driveshaft is somehow out of tolerance (i.e. it's not supposed to have the large amount of play that it does have)
3. The new driveshaft design gets rid of the "tink" (which was mildly annoying, and caused all my mechanic friends to incorrectly say "you need new u-joints"), and replaces it with an anoying hollow resonant sound that is frankly more annoying than the tink ever was!
I called my Chevrolet dealer and told the service rep that I don't like this new driveshaft, and either want a new one that does not make the noise, OR I want to go back to my old one (tick is better than the noise). He is checking to see if they still have my old one!
The dealer invted me to come in Monday to continue "The driveshaft story"!
I'll let you guys know what happens next.
Isn't owning an SSR fun?
Jim G
