C4 Tech/Performance L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

Rear End knocking noise

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Old Aug 27, 2015 | 02:24 PM
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Default Rear End knocking noise

My '86 with 88K miles and automatic has developed a rear end noise that sounds like a knock at several times a second. It is not a grinding or higher frequency noise. I notice it at higher speeds (30 or more MPH) whether accelerating or coasting. It is not particularly loud but still annoying.
Just wondering if it could be universal joints or a rear bearing. I cannot tell if it is coming from one side or both. Any ideas?
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Old Aug 27, 2015 | 09:35 PM
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The only way to tell is to get under there and see if anything is loose. At 88K it wouldn't be the worst idea to change the 6 U-joints anyway. Could also be a wheel bearing or even a brake issue.
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Old Aug 28, 2015 | 11:42 AM
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Originally Posted by jv9999
The only way to tell is to get under there and see if anything is loose. At 88K it wouldn't be the worst idea to change the 6 U-joints anyway. Could also be a wheel bearing or even a brake issue.
Have you taken a look at the hub bearings, raise up and support the car grab ahold of wheels and see if there is play in the wheels.
If you have the car Properly supported start the car drop into gear and give a look no touch inspection (we don't want an episode of the day I did something dumb) listen for your noise
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Old Aug 29, 2015 | 09:50 PM
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I jacked up the rear end today and checked for looseness on the rear wheels. There was excessive play. I started it up and ran in gear and definitely heard the familiar knocking noise. While under there, I checked the U joints on the drive shaft and half shafts. Everything was tight.

Looks like I will be replacing the rear bearing assemblies. From what I have read, it is not a particularly difficult job.
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Old Aug 30, 2015 | 02:35 PM
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Originally Posted by abdo
I jacked up the rear end today and checked for looseness on the rear wheels. There was excessive play. I started it up and ran in gear and definitely heard the familiar knocking noise. While under there, I checked the U joints on the drive shaft and half shafts. Everything was tight.

Looks like I will be replacing the rear bearing assemblies. From what I have read, it is not a particularly difficult job.
Before to replace them, i would take a look at three t55 bolts, are them well tighted? 67 ft/lb is for mine

Even look at 36mm spindle nut...it should be around 164 ft/lb for mine is that dont know your year
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