Differential issues after a track day
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From: Tampa FL
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Differential issues after a track day
I went to the track this weekend, and now I feel a vibration in the car when I accelerate while turning at slow speeds. It doesn’t do this while going in a straight line. I’m thinking I’ve somehow done something to the differential (But I’m not 100% sure it is the differential though). I had mobile 1 synthetic fluid in it, as well as a limited slip additive. Any idea on what’s possibly been done, or what I should do next to diagnose or repair the problem?
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Joined: Dec 1999
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From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
Jack up each wheel one at a time and check to see if you can feel any lateral movement in the bearings when you grasp the front tires at the 12:00 & 6:00 position and push/pull inward/outward. The rear tires can be tested at the 12:00 & 6:00 and 3:00 & 9:00 positions also. If you can visibly see it, its for sure is too much.
I use a dial indicator set up to see lost motion from the caliper to the rotor. 0.008" is the MAX spec. Make sure that your not set up to also see A arm movement!
Those rubber bushings flex a LOT!!!!
If you have a wheel bearing that is going bad, you will feel and maybe hear noise when you turn in a direction to LOAD that bearing. They do go bad, especially if you drive them very hard.
Ive see 3-4 bad ones. Mostly in the rear.
I use a dial indicator set up to see lost motion from the caliper to the rotor. 0.008" is the MAX spec. Make sure that your not set up to also see A arm movement!
Those rubber bushings flex a LOT!!!! If you have a wheel bearing that is going bad, you will feel and maybe hear noise when you turn in a direction to LOAD that bearing. They do go bad, especially if you drive them very hard.
Ive see 3-4 bad ones. Mostly in the rear.
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No play that I can "feel" or see. I placed the car on jacks on the lower control arm to test it better (To avoid feeling the play in the lower control arm bushings). I'm having an issue getting my dial indicator hooked to the caliper to measure the play between it and the rim. Are there any other ways to test the bearings?
I also put the car in neutral, backed out the brake pads a bit and turned the wheel by hand. I didn't notice or hear anything abnormal.
I drained the fluid from the diff. It looks like it was in great shape. Now the one strange thing that occurred is when I took out the drain plug, it started sucking in air, kind of like it was under a good vacuum.
I also put the car in neutral, backed out the brake pads a bit and turned the wheel by hand. I didn't notice or hear anything abnormal.
I drained the fluid from the diff. It looks like it was in great shape. Now the one strange thing that occurred is when I took out the drain plug, it started sucking in air, kind of like it was under a good vacuum.
Last edited by JMon; Jun 17, 2008 at 08:27 AM.
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Joined: Sep 2003
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From: Raleigh / Rolesville NC
I went to the track this weekend, and now I feel a vibration in the car when I accelerate while turning at slow speeds. It doesn’t do this while going in a straight line. I’m thinking I’ve somehow done something to the differential (But I’m not 100% sure it is the differential though). I had mobile 1 synthetic fluid in it, as well as a limited slip additive. Any idea on what’s possibly been done, or what I should do next to diagnose or repair the problem?
How much use do the wheel bearings have?
Yes changing he trans and diff fluid to synthetic is very important
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
No play that I can "feel" or see. I placed the car on jacks on the lower control arm to test it better (To avoid feeling the play in the lower control arm bushings). I'm having an issue getting my dial indicator hooked to the caliper to measure the play between it and the rim. Are there any other ways to test the bearings?
I also put the car in neutral, backed out the brake pads a bit and turned the wheel by hand. I didn't notice or hear anything abnormal.
I drained the fluid from the diff. It looks like it was in great shape. Now the one strange thing that occurred is when I took out the drain plug, it started sucking in air, kind of like it was under a good vacuum.
I also put the car in neutral, backed out the brake pads a bit and turned the wheel by hand. I didn't notice or hear anything abnormal.
I drained the fluid from the diff. It looks like it was in great shape. Now the one strange thing that occurred is when I took out the drain plug, it started sucking in air, kind of like it was under a good vacuum.
Ha,,,Thats a GOOD sign! The diff has a check valve in the vent that lets pressure OUT but keeps the air from entering.!!! It keeps the DIFF at a "SLIGHT" vacuum and thus, "HELPS" prevent leaks! When the diff heats up the pressure escapes and when the DIFF cools down, it keeps the DIFF in a slight vacuum. So,,yours is working CORRECTLY!
BC
