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Nice Weather, Please?
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Discussion Starter · #1 ·
Over the winter I installed Koni Shocks, Eibach Springs, Whiteline Rear sub-frame Inserts, and Torque Solution Differential Bushings, Whiteline front Poly strut mounts, and Eagle F1 tires.

Let the springs settle for 75 miles, got it aligned, and have since driven it another 100 miles or so.

So with all that being said, I have been having a slight thump/clunk everytime I slow down to a stop. It happens between 10mph and 0mph. It sounds sort of like putting a manual transmission into 1st gear while rolling (clutch in obviously). I haven't noticed any other noises, so I figured I would recheck all sub-frame bolts and differential bolts, but I am to assume this is normal NVH from installing these parts?

Finally, I just read on the forums that I should "re-clock" or "index" the front control arm bushings bolts after lowering the car. Is this something that should be done, and will it now throw off my alignment?
 

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Nice Weather, Please?
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Discussion Starter · #4 ·
That is an interesting suggestion, I will drive it in manual mode and see if it changes anything.
 

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That is an interesting suggestion, I will drive it in manual mode and see if it changes anything.
that may or may not work. I know that, with my tune at least, the car still downshifts on its own even in manual mode when coming to a stop

but you could slide it in neutral when slowing down to see if it does it then....
 

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Nice Weather, Please?
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Discussion Starter · #6 ·
Makes sense. Would a shift in the transmission be felt that much more in the differential because of the bushings?
 

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Nice Weather, Please?
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Discussion Starter · #7 ·
Ok so this noise only happens when in gear. If I put the car in neutral while stopping, no noise whatsoever. I checked all the bolts but my torque wrench is too long to spec the diff mount bolts. Probably just normal nvh from poly diff bushings.
 

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I have the same clunk when coming to a stop. It's in sync with a 2nd to 1st gear downshift. I think it has something to do with the driveline, not suspension. My car is at the dealer now getting looked at and I asked him to check the DS for wearing issues.
 

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Nice Weather, Please?
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Discussion Starter · #10 ·
I agree that is something with the drive line. When in neutral, no noise. I am just going to verify torque specs, and chalk it up to normal because of the Poly Bushings.
 

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I think its the new bushings causing the noise
 

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Strange - I get an email this morning saying that GMCustomerService posted to this thread but I don't see the post anywhere. Was it deleted?

Anyway - to answer GM's question - I still have the issue when the car is in drive (manual, auto, sport) but not in neutral. The dealer checked the shaft and didn't find any issues. He also changed the trans fluid but it's still happening. Not a big deal though. If it gets worse I will follow up.

As for my bushings - they're poly strut tower bushings so shouldn't have anything to do with shifting issues.
 

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Its Good To Be Tha King
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Over the winter I installed Torque Solution Differential Bushings.

So with all that being said, I have been having a slight thump/clunk everytime I slow down to a stop.
I think I may have found your cause of hearing the downshift into first.

May want to try a lower durometer polyurethane bushing.
 

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Its Good To Be Tha King
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FWIW, I believe your bushing set is 85 durometer.

BMR has a street set which is 68 durometer (what I'm running)

and a pro version at 95 durometer

and a race version made out of CNC-machined from Delrin plastic
 

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But he save $2.91 over BMR or Whiteline bushings.
 

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Nice Weather, Please?
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Discussion Starter · #20 ·
I think I may have found your cause of hearing the downshift into first.

May want to try a lower durometer polyurethane bushing.
You are probably correct. Didn't realize there was such a difference in the durometer, if I get annoyed enough ill swap them out again. Thank you!


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