Rear of car clunks while cornering

Drivetrain discussion including Transmission, Differential, Driveshaft, and related items.
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jj55chevy
Posts: 54
Joined: Wed Dec 19, 2018 6:37 pm

Rear of car clunks while cornering

Post by jj55chevy »

My car just started making noise last week. it is like a clunking noise when I take a right turn.....then this weekend it got way worse...now it makes multiple clunks turning in either direction.....all is fine and quiet when I am driving straight....my guess is the posi is going out? If I do have to replace the rearend I am thinking of looking for a non posi unit because I drive my car year round and it is totally worthless in the winter.....thoughts anyone?
GammaFlat
Posts: 260
Joined: Mon Sep 21, 2020 9:26 am
Location: NW Indiana

Re: Rear of car clunks while cornering

Post by GammaFlat »

I seem to recall that when I changed my differential (to a 3.27), I had read (here on the forum) that performing some figure 8 type maneuvers after you change the fluid would "stop the noise" back there. I do seem to recall mine making noise at first.

Before I did anything else, I would change the fluid. Look at the fluid for signs of "bad behavior" (shiny stuff). Also, is it possible you have the wrong fluid in there? They are very persnickety about fluid type. GM changed the standard of fluids from "some fluid with some additive" to just "some fluid". The fact that the behavior changed kind of suddenly all but rules this out.

If you care about performance, maybe you want to upgrade to a 3.45 or a 3.27. If it does end up that your rear end is bad, there are plenty of folks on this forum with a factory center section (2.92) in inventory 8-) ... like me. Shipping is the big problem.

If you don't care about performance, the 6 cylinder automatic Camaros have a weaker but cheaper rear end that will work. I think it may not be posi. My understanding is that there are 3 sizes of the ring gear. The Camaro has the biggest ring. Our car has a "medium" ring. The 6 cylinder Camaro is the smallest. Larger ring = stronger.
Current: 2013 9C3, deeper trans pan, 12VoltSolutions Remote, Class III hitch, Android Auto capable radio
jj55chevy
Posts: 54
Joined: Wed Dec 19, 2018 6:37 pm

Re: Rear of car clunks while cornering

Post by jj55chevy »

GammaFlat wrote: Mon Jul 18, 2022 4:03 pm I seem to recall that when I changed my differential (to a 3.27), I had read (here on the forum) that performing some figure 8 type maneuvers after you change the fluid would "stop the noise" back there. I do seem to recall mine making noise at first.

Before I did anything else, I would change the fluid. Look at the fluid for signs of "bad behavior" (shiny stuff). Also, is it possible you have the wrong fluid in there? They are very persnickety about fluid type. GM changed the standard of fluids from "some fluid with some additive" to just "some fluid". The fact that the behavior changed kind of suddenly all but rules this out.

If you care about performance, maybe you want to upgrade to a 3.45 or a 3.27. If it does end up that your rear end is bad, there are plenty of folks on this forum with a factory center section (2.92) in inventory 8-) ... like me. Shipping is the big problem.

If you don't care about performance, the 6 cylinder automatic Camaros have a weaker but cheaper rear end that will work. I think it may not be posi. My understanding is that there are 3 sizes of the ring gear. The Camaro has the biggest ring. Our car has a "medium" ring. The 6 cylinder Camaro is the smallest. Larger ring = stronger.
thank you for your input! I have had the car for about 3 years with no problems so the fluid was not recently changed. It just started clunking in the last week then the last day that I drove it it got really bad....I jacked it up and even though it >was< a posi the tires were rotating in the opposite direction while the car was in park. even worse it would only turn a quarter turn on the passenger side and it would go a couple revolutions on the drivers side...I assumed the 3rd member was toast so I pulled it. Now I am looking for a replacement...I get enough fun out of this car so I am content with the same setup.....but I am also tempted on looking for a non posi to take the fishtailing out of it when I drive it in the winter.......all told, does anyone by the twin cities have a 3rd member for sale?
jj55chevy
Posts: 54
Joined: Wed Dec 19, 2018 6:37 pm

Re: Rear of car clunks while cornering

Post by jj55chevy »

I did find another rearend today and will know tomorrow if it cures my problem
jj55chevy
Posts: 54
Joined: Wed Dec 19, 2018 6:37 pm

Re: Rear of car clunks while cornering

Post by jj55chevy »

all is quiet in the land.....the replacement rearend took car of the clunk and the ujoint sounding clunk )even though it does not have a ujoint) that it would do going into 2nd gear.
JoeR
Posts: 150
Joined: Wed May 25, 2022 12:34 am
Location: Central, NC

Re: Rear of car clunks while cornering

Post by JoeR »

Excellent. Glad you got it diagnosed and repaired.
Joe
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