Cadillac CTS-V - Changed differential bushing and added support block.

And now my car differential whines. I am not sure if it was there before but it it is more noticeable now. It's only on light throttle and louder in 5th and 6th gear highway speeds. The whine is not that loud and some people might not even tell it's there but I certainly did notice. I guess because it was being extra attentive looking for that differential clunk...
Anybody else notice this after installing the CS bushing and support block?

Yes. I noticed the same thing, but I had the entire back end of the interior out. With the back seat reinstalled, I can't hear the differential, period.

Yep 5th and 6th gear for me as well

Yep 5th and 6th gear for me as well
Was this after the bushing and support block installed?

Yes after the install is was much more noticeable

Just went out for another dirve and the whine is not too bad. Just turning on the radio at low valume and you can't hear it anymore. I can almost bet my left huevo that the differential oil has never been changed @ 89k miles.. I wonder if I use a heavier weight lubricant, the whine will completely dissappear. Anybody tried this?

The same thing happened to me. I'm still glad I did it, though. Well worth the whine to have a car that can deliver power to the wheels exactly when I want it.

I installed bushing and bmr pinion brace and when letting out on the clutch sometimes it clunks but the cultch in clunk is gone... Idk what's going on but mine wines also . Checked bolts and there all tight. It sounds like the front diff bolt is loose tho? Any suggestions

I installed bushing and bmr pinion brace and when letting out on the clutch sometimes it clunks but the cultch in clunk is gone... Idk what's going on but mine wines also . Checked bolts and there all tight. It sounds like the front diff bolt is loose tho? Any suggestions
Why do you suspect it's loose?

Same for me after installing same items 55-70mph after 15mins of driving fades out past 70mph.

Same exact thing for me but I don't mind that much. More reason to save for the 8.8 CS kit.

Just went out for another dirve and the whine is not too bad. Just turning on the radio at low valume and you can't hear it anymore. I can almost bet my left huevo that the differential oil has never been changed @ 89k miles.. I wonder if I use a heavier weight lubricant, the whine will completely dissappear. Anybody tried this?

89k and never changed?? Change it ASAP! Stick with 75w90.

CS block and bushing didn't add that much whine...to my 4th gen diff.

Yes. I noticed the same thing, but I had the entire back end of the interior out. With the back seat reinstalled, I can't hear the differential, period.

So....wouldn't that be a No? (entire back end of interior out doesn't count, does it?)

I just added a UUC and the support block. The whine is pretty bad starting at about 30 and going up to about 55 mph then it starts going away. My diff had whine before I changed the bushing so I am not all that surprised. The whine can change depending on load on or off of the diff. I have thicker fluid in my rear allready also.

89k and never changed?? Change it ASAP! Stick with 75w90.

CS block and bushing didn't add that much whine...to my 4th gen diff.

75W-140 provides better protection during high temperature operation. I recommend Redline 75W140 GL-5.

Ahhhh.....I forgot how annoying that whine was.

The harder bushings are going to accentuate the whine. I tried heavier fluid in my stocker when I had it, and it was only a very slight difference in quieting it down.

I'm so glad my 9' doesn't whine :)