Rear-end road noise
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brackie1
- Posts: 523
- Joined: Sat Dec 14, 2013 1:24 pm
- Your car is a: 1978 124 spider
- Location: Winston-Salem, NC
Rear-end road noise
Just developed a new noise. Mine is a '77 2 piece differential. How can you determine whether noise is a rear wheel bearing or the differential.
Gene
North Carolina
North Carolina
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18Fiatsandcounting
- Posts: 3799
- Joined: Fri Mar 15, 2019 11:23 pm
- Your car is a: 1969 and 1971 124 spiders
- Location: San Francisco Bay Area
Re: Rear-end road noise
Well, you could do like my father did with his '69 spider (true story) and put me as a 10-year old in the trunk and drive around and ask me to identify where the noise was coming from.
While that might help, a few questions for your issue: Is the noise constant, or does it matter whether your car is accelerating, coasting, steady speed? Same noise whether hot or cold? Does the noise get worse when more people (more weight) are in the car?
-Bryan
While that might help, a few questions for your issue: Is the noise constant, or does it matter whether your car is accelerating, coasting, steady speed? Same noise whether hot or cold? Does the noise get worse when more people (more weight) are in the car?
-Bryan
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brackie1
- Posts: 523
- Joined: Sat Dec 14, 2013 1:24 pm
- Your car is a: 1978 124 spider
- Location: Winston-Salem, NC
Re: Rear-end road noise
The noise goes up and down as i accelerate and decelerate. Begins immediately after starting to drive. It is a whinnying kind of noise. It shifts fine it accelerates well.
Gene
North Carolina
North Carolina
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18Fiatsandcounting
- Posts: 3799
- Joined: Fri Mar 15, 2019 11:23 pm
- Your car is a: 1969 and 1971 124 spiders
- Location: San Francisco Bay Area
Re: Rear-end road noise
Hmmm, could be almost anything in the drivetrain: differential, wheel bearings, transmission bearings, driveshaft center support bearing, etc.
If you are sure the noise is coming from the rear and not the middle or front, I'd start by checking the oil level in the differential. If that's OK, I'd take off both rear wheels and the rear brake calipers and rotors and then see if you can move the flanges on the two axle half-shafts and see if there is any noticeable play. In and out, side to side, up and down. You might be able to do this while the brakes are still in place, but it's harder to see if there's movement. While you're down there, check if there's any play in the driveshaft input to the differential.
Use caution while being under the car of course, preferably with solid jack stands.
-Bryan
If you are sure the noise is coming from the rear and not the middle or front, I'd start by checking the oil level in the differential. If that's OK, I'd take off both rear wheels and the rear brake calipers and rotors and then see if you can move the flanges on the two axle half-shafts and see if there is any noticeable play. In and out, side to side, up and down. You might be able to do this while the brakes are still in place, but it's harder to see if there's movement. While you're down there, check if there's any play in the driveshaft input to the differential.
Use caution while being under the car of course, preferably with solid jack stands.
-Bryan
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grrrdot
- Posts: 225
- Joined: Mon Jan 02, 2012 11:14 pm
- Your car is a: 1967 124
Re: Rear-end road noise
In my experience:
Wheel bearing noise typically comes from one corner of the car and gets better or worse as you turn. e.g. when you turn left the weight of the car shifts and the right side wheel bearings take more load and if bad get noisy. Usually this is the most evident at highway speeds ( Push in the clutch so you don't just hear screaming engine )
Unless its really gone rear end noise comes generally from behind you and is most evident when accelerating or decelerating, when just coasting its usually pretty quiet. Typically it also doesn't care if your turning right or left. Having someone in the "back seat" can also help in diagnosing things.
Center support bearing is a lot like the rear end in that its accel/decel but the noise is closer to under you as opposed to behind you.
And lastly transmission noise is a "feature" of classic Fiat 124s
-G
Wheel bearing noise typically comes from one corner of the car and gets better or worse as you turn. e.g. when you turn left the weight of the car shifts and the right side wheel bearings take more load and if bad get noisy. Usually this is the most evident at highway speeds ( Push in the clutch so you don't just hear screaming engine )
Unless its really gone rear end noise comes generally from behind you and is most evident when accelerating or decelerating, when just coasting its usually pretty quiet. Typically it also doesn't care if your turning right or left. Having someone in the "back seat" can also help in diagnosing things.
Center support bearing is a lot like the rear end in that its accel/decel but the noise is closer to under you as opposed to behind you.
And lastly transmission noise is a "feature" of classic Fiat 124s
-G