Cadillac Owners Forum banner
  • Hey everyone! Enter your ride HERE to be a part of MAY's Ride of the Month Challenge!

1 - 9 of 9 Posts

·
Registered
Joined
·
41 Posts
Discussion Starter · #1 ·
I am starting to drive my 04 V more often. The car is low mileage and perfect except for driveline vibration and noises.

I NEED SOME HELP HERE...

The car is stock except for the dealer provided, Borla catback exhaust and upgraded brake rotors.

The rear diff and trans to dif, driveline have been replaced under warranty.


Here are the symptoms:

* Oscillating groan from rear end when backing around turns and often when going forward in tight turns. It seems to be less once the car warms up. I suspect that this is from the differential clutch pack and perhaps the wrong oil in the diff.

* Nasty harmonic vibration under light to feather throttle load in 6th gear at 65MPH to @75-80 MPH. There is zero feedback of this vibration in the shift lever. The vibration is enough to blur the rear view mirror vision and it is very audible in the rear seat. The vibration is much less intense in 5th gear at the same speeds.

I'd really like to learn of a solid, aftermarket upgrade to this common problem on this car.

Any and all help is appreciated.
 

·
Registered
'05 CTS-V, '00 SLS, 98 SLS, 89 Eldo, '80 Eldo
Joined
·
4,001 Posts
First thing I would do is change the fluid in the diff to a heavier weight.
Vibration could possibly be that the drive shaft was not re-installed properly. Are you sure it's not from the exhaust?
Well, that's my .02 anyways.
 

·
Registered
17 xt5 & Blk 05 cts-v
Joined
·
2,470 Posts
I had what you describe at 70k miles. i changed the read diff fluid. took care of it.
 

·
2016 ATS Premium 6-spd MT
Joined
·
14,209 Posts
I might be wrong, but before you change to a different weight lube, I can tell you that five years ago guys here were reporting that inexperienced dealers were neglecting to put the anti-slip additive in the diff when they changed the fluid. The symptoms you report were similar to theirs.

Get hold of C66 Racing and get some his Amsoil Severe Gear 75W-90 in your diff. I also put a bottle of the Slip Lock additive in, but I think it already includes it. MUCH cheaper swapping out the fluid than slinging a wrench and tearing into the diff needlessly. Just my $0.02.
 

·
Registered
'05 CTS-V, '00 SLS, 98 SLS, 89 Eldo, '80 Eldo
Joined
·
4,001 Posts
I might be wrong, but before you change to a different weight lube, I can tell you that five years ago guys here were reporting that inexperienced dealers were neglecting to put the anti-slip additive in the diff when they changed the fluid. The symptoms you report were similar to theirs.

Get hold of C66 Racing and get some his Amsoil Severe Gear 75W-90 in your diff. I also put a bottle of the Slip Lock additive in, but I think it already includes it. MUCH cheaper swapping out the fluid than slinging a wrench and tearing into the diff needlessly. Just my $0.02.
I've got 15k miles on my Amsoil diff fluid. No additive, and no problems either
As soon as I can figure out which diff bushing to go with, I'll try the higher weight stuff.
 

·
Registered
Joined
·
41 Posts
Discussion Starter · #8 ·
Thanks again but can you be clear on the fix:

Did the diff fluid change solve the groaning, the vibration or both?
 

·
Registered
04' Blown CTS-V 554rwhp 497rwtq
Joined
·
1,786 Posts
Thanks again but can you be clear on the fix:

Did the diff fluid change solve the groaning, the vibration or both?
It is to difficult to tell you yes or no for your specific application. Your "groan" may be my "squeak" while Tony's "rattle" might be your "vibration". Get my point? Just upgrade your diff fluid with Amsoil (PM C66 Racing for dealer cost) and then go from there. Fluid is cheap and easy and where you should start.
 
1 - 9 of 9 Posts
Top