Poly diff bushings, vibration?

[Bottledbird68]

So, was reading about poly diff bushings and sometimes people hear more noise. I don’t see anything about feeling more vibration. Is there more vibration feel in some cases or just gear noise?
Long story short, swapped out my 3.91 geared factory diff, axles, and driveshaft with a lingenfelter 9.5” rear, matching axles, and driveshaft. Car was smooth before. Now around 75ish on up I feel a slight vibration. If it’s just a poly diff bushing thing I’m fine with it. I don’t mind. I just want to make sure it’s not a bigger issue. Any input from guys who’ve run poly diff bushings before?

[Pro-tuned]

Yes poly bushings can contribute to vibrations.

[acammer]

I did poly bushing in the diff when I did the 4.10's. I didn't pick up any vibrations at all. I do appreciate a little more noise doing tight parking lot speed turns - you can hear the LSD clutches. I also get a little gear noise rolling through 40 to 50 mph under real light loads. But other than that it's silent, and no vibration. I would suspect the driveshaft, not the rear. That 9.5 inch should be fun to hammer on! What gear did you go with?

[Bottledbird68]

Went with the 4.10’s. Im looking forward to being able to play with it now lol. I’m curious if it’s the driveshaft too or not.
Those that have experienced vibration how much was it? Car is pretty smooth down low. At 80 it kinda feels like a massage chair on low lol

[BMR Sales]

Originally Posted by Pro-tuned

Yes poly bushings can contribute to vibrations.

No they don't.

the situation is that when you replace a soft Rubber Bushing at your diff with a Harder Material (Poly - it has to be high durameter to last or Delrin), there is less deflection of Noise & Vibration that comes from the Diff. The Bushings do not contribute, they transmit the NVH.

[Bottledbird68]

Originally Posted by BMR Sales

No they don't.

the situation is that when you replace a soft Rubber Bushing at your diff with a Harder Material (Poly - it has to be high durameter to last or Delrin), there is less deflection of Noise & Vibration that comes from the Diff. The Bushings do not contribute, they transmit the NVH.

Ok. So there’s a chance then that what I’m feeling is normal for poly diff bushings? If it is I’m cool with it. Just want to make sure I’m not damaging anything.

[acammer]

Originally Posted by Bottledbird68

Ok. So there’s a chance then that what I’m feeling is normal for poly diff bushings? If it is I’m cool with it. Just want to make sure I’m not damaging anything.

You have a vibration from an out of balance component. Assuming it's the same tires and you didn't feel it before, it's probably the drive-train. The most likely component there is the driveshaft. The bushings don't cause it -it shouldn't vibrate. You notice it more because of the bushings, but they aren't at fault.

[fif_gen_powa]

Originally Posted by Bottledbird68

Ok. So there’s a chance then that what I’m feeling is normal for poly diff bushings? If it is I’m cool with it. Just want to make sure I’m not damaging anything.

No, what bmr is saying is the poly bushing itself does not vibrate but will transmit a vibration that the stock bushing might have absorbed and masked.

[Bottledbird68]

Originally Posted by fif_gen_powa

No, what bmr is saying is the poly bushing itself does not vibrate but will transmit a vibration that the stock bushing might have absorbed and masked.

I get that. I suppose my question worded better is how much vibration do the stock bushings mask?

[fif_gen_powa]

Originally Posted by Bottledbird68

I get that. I suppose my question worded better is how much vibration do the stock bushings mask?

There should not be any noticeable vibration. Most common would be wheels and tires out of balance. Next step would be get the car on a lift to pinpoint the issue. If the driveshaft is two piece check the carrier bearing, if its a one piece contact a local driveshaft shop for balancing

[Bottledbird68]

Originally Posted by fif_gen_powa

There should not be any noticeable vibration. Most common would be wheels and tires out of balance. Next step would be get the car on a lift to pinpoint the issue. If the driveshaft is two piece check the carrier bearing, if its a one piece contact a local driveshaft shop for balancing

Well wheels are fine. They are the same ones as before and didn’t have any vibration. It is a two piece shaft. Carrier bearing looks mint. Double checked it before I put it in.

[alaskacamaro]

Op, get a good quality loud exhaust, the bushing noise will go away and all you will hear is the sweet sweet sound of unrestictive engine. Like me. 😊

[Bottledbird68]

Originally Posted by alaskacamaro

Op, get a good quality loud exhaust, the bushing noise will go away and all you will hear is the sweet sweet sound of unrestictive engine. Like me. ��

I already have long tubes, no cats, and a Mach solo exhaust. I can’t hear any noise at all lmao �� If all it was was noise I wouldn’t even care honestly.
However it feels like I installed a massage chair on low at 80mph+ After talking with DSS I think I’m going to be ordering a one piece aluminum shaft this week and see if that solves my issue.
The 6 week wait they quoted though for a custom shaft is going to be painful though. This setup is older so they don’t stock anything for it anymore...

[2010_camaro]

Originally Posted by Bottledbird68

So, was reading about poly diff bushings and sometimes people hear more noise. I don’t see anything about feeling more vibration. Is there more vibration feel in some cases or just gear noise?
Long story short, swapped out my 3.91 geared factory diff, axles, and driveshaft with a lingenfelter 9.5” rear, matching axles, and driveshaft. Car was smooth before. Now around 75ish on up I feel a slight vibration. If it’s just a poly diff bushing thing I’m fine with it. I don’t mind. I just want to make sure it’s not a bigger issue. Any input from guys who’ve run poly diff bushings before?

If you decided to get a set let me know. I have a set of derlins I took out when I make some suspension charges.