Diff noise
09-12-2011 | 05:32 AM
#1
Thread Starter
Joined: Jun 2010
Posts: 1,019
Likes: 8
From: Baltimore, MD
Diff noise
On Tuesday, Sept 5, my car started making a weird noise whenever I was decelerating, but only after driving for 20 minutes or more. Here's a vid of the noise.
http://www.youtube.com/watch?v=WXvOd2G1wgg
When I researched the symptoms on this site and talked to some gear heads I knew in person, it led me to believe it was a wheel bearing. I took the car in to the Goodyear Service Center, where I got the state inspection and where I usually get new tires mounted, and told them I suspected a wheel bearing was bad. They said nothing seemed to be wrong. Luckily they didn't charge me for looking.
I then took it to Agile Auto after seeing that some of you guys go there. They took their time looking at the car, and driving it around to listen to the noise. The mechanic there said the wheel bearings, tires, suspension, and brakes are all fine, and he suspect the sound is somewhere in the drivetrain. He has a hunch that it's coming from the diff, maybe a shattered rod or tooth (whatever the things are called, haha). They want me to come back so they can load the drivetrain up on their dyno (which was booked solid the day I took it in) to make sure the sound is coming from the diff before they start taking it apart or replace it.
What do you guys think?
Anyone looking to sell an AP1 diff? lol
http://www.youtube.com/watch?v=WXvOd2G1wgg
When I researched the symptoms on this site and talked to some gear heads I knew in person, it led me to believe it was a wheel bearing. I took the car in to the Goodyear Service Center, where I got the state inspection and where I usually get new tires mounted, and told them I suspected a wheel bearing was bad. They said nothing seemed to be wrong. Luckily they didn't charge me for looking.
I then took it to Agile Auto after seeing that some of you guys go there. They took their time looking at the car, and driving it around to listen to the noise. The mechanic there said the wheel bearings, tires, suspension, and brakes are all fine, and he suspect the sound is somewhere in the drivetrain. He has a hunch that it's coming from the diff, maybe a shattered rod or tooth (whatever the things are called, haha). They want me to come back so they can load the drivetrain up on their dyno (which was booked solid the day I took it in) to make sure the sound is coming from the diff before they start taking it apart or replace it.
What do you guys think?
Anyone looking to sell an AP1 diff? lol
09-12-2011 | 06:39 AM
#3
Joined: Nov 2002
Posts: 16,698
Likes: 70
From: High Knob Mountain
Diff noise will change under small throttle application in a straight line.
Why not drop the change the fluid and look for tell tale bits of metal? It might last for a while with new fluid, putting it in a dyno will just kill it right there.
Why not drop the change the fluid and look for tell tale bits of metal? It might last for a while with new fluid, putting it in a dyno will just kill it right there.
09-12-2011 | 07:13 AM
#4
Thread Starter
Joined: Jun 2010
Posts: 1,019
Likes: 8
From: Baltimore, MD
From what I understood the guys at Agile Auto don't want to do a full blown dyno pull, they just want to safely get the wheels moving with the car in the air to try and pinpoint the noise. I'm sure my S has lost some horses over it's 110K miles, but it's still fast enough to be fun for me.
Looking at the fluid is probably a good idea. I changed the fluid in July when the car was at 105K miles and it didn't seem to have any metal parts in it. The car now has 110K miles, and I've changed the fluid every 15K miles since I bought it with 70K.
Looking at the fluid is probably a good idea. I changed the fluid in July when the car was at 105K miles and it didn't seem to have any metal parts in it. The car now has 110K miles, and I've changed the fluid every 15K miles since I bought it with 70K.
09-12-2011 | 08:17 AM
#5
Community Organizer
Joined: Nov 2005
Posts: 16,546
Likes: 711
From: Maryland
Just for reference this is what my diff sounded like when I broke off one of the teeth on the final drive. Yours sounds much different.
http://www.youtube.com/watch?v=jEJUV7M7GdA
http://www.youtube.com/watch?v=jEJUV7M7GdA
09-12-2011 | 09:06 AM
#6
Joined: May 2008
Posts: 9,557
Likes: 15
From: MD
For reference, here's what my wheel bearing sounded like in early stages of failure.
It would only make the noise after driving around for a while. One key factor was the the noise changed when weaving left to right. It went away completely while going left. That might not rule the diff out entirely though, since turning also changes the speeds of the rear wheels, which could affect a noise from the diff.
Do you know what the shop did to rule out the wheel bearing?
I agree about draining the diff and looking for chunks, but also consider the wheel bearing a little further, I think. At the early stages of failure, your wheel won't be loose when you shake it or anything like that. I think it would be very difficult to tell just by inspecting the car.
http://www.youtube.com/watch?v=Fsw_EwnUcGU
It would only make the noise after driving around for a while. One key factor was the the noise changed when weaving left to right. It went away completely while going left. That might not rule the diff out entirely though, since turning also changes the speeds of the rear wheels, which could affect a noise from the diff.
Do you know what the shop did to rule out the wheel bearing?
I agree about draining the diff and looking for chunks, but also consider the wheel bearing a little further, I think. At the early stages of failure, your wheel won't be loose when you shake it or anything like that. I think it would be very difficult to tell just by inspecting the car.
http://www.youtube.com/watch?v=Fsw_EwnUcGU
09-12-2011 | 10:11 AM
#7
Thread Starter
Joined: Jun 2010
Posts: 1,019
Likes: 8
From: Baltimore, MD
For reference, here's what my wheel bearing sounded like in early stages of failure.
It would only make the noise after driving around for a while. One key factor was the the noise changed when weaving left to right. It went away completely while going left. That might not rule the diff out entirely though, since turning also changes the speeds of the rear wheels, which could affect a noise from the diff.
Do you know what the shop did to rule out the wheel bearing?
I agree about draining the diff and looking for chunks, but also consider the wheel bearing a little further, I think. At the early stages of failure, your wheel won't be loose when you shake it or anything like that. I think it would be very difficult to tell just by inspecting the car.
http://www.youtube.c...h?v=Fsw_EwnUcGU
It would only make the noise after driving around for a while. One key factor was the the noise changed when weaving left to right. It went away completely while going left. That might not rule the diff out entirely though, since turning also changes the speeds of the rear wheels, which could affect a noise from the diff.
Do you know what the shop did to rule out the wheel bearing?
I agree about draining the diff and looking for chunks, but also consider the wheel bearing a little further, I think. At the early stages of failure, your wheel won't be loose when you shake it or anything like that. I think it would be very difficult to tell just by inspecting the car.
http://www.youtube.c...h?v=Fsw_EwnUcGU
I don't know what the shop did for testing the wheel bearing. When i get a chance I'm going to lift the car up myself and see if there's any play.
Hopefully mine is an early wheel bearing issue like yours was. I haven't done any clutch dumps or burnouts so I hope it's not the diff. All I've done is drive it through snow and about 10 autocrosses
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09-12-2011 | 06:45 PM
#9
Registered User
Joined: Apr 2011
Posts: 21
Likes: 0
I had this same exact noise so I replaced the wheel bearing on my right rear wheel since thats where the noise came from. Later that day the noise was back and I started fearing that my diff was done but before I gave up I took it to my buddies shop and they found a build-up of rust between the driveshaft and wheel hub....they cleaned it up and put some anti seize. I have been noise free for 1 week!
