: Just bought my V... how can I tell if the diff has been upgraded?



smbstyle
06-20-10, 08:42 PM
I just bought a one-owner 04 CTS-V from a local dealer in Sarasota (where the car was purchased brand new by the original owner), has 51k miles, and is mint. Car drives perfectly, no clunk, no whining, it was very well maintained by a Cardiologist in the area.

My only issue is I have no idea if the original diff has been replaced under warranty or not, and I have seen that those who have had the diffs replaced under warranty have received the 06+ parts which, from what I have read, hold up a lot better than the 04-05's. The only receipts I have are from the dealer who replaced the front motor mount, front brake pads and front differential bushing, but that is it.

So, here is my question, how can I tell if the diff is an 06+ setup and the original owner has taken care of the issues, or if everything is still original?

My plan either way is to get the Hendrix axle, BMR wheelhop kit and pinion brace to keep the diff alive. I dont plan on drag racing the car much at all, mainly 5 or 6 auto-x events a year and about one or two trips to Sebring each year.

Gus_Mahn
06-20-10, 09:08 PM
Safely jack it up, support it, and crawl under it. While there, get the numbers off the tag on the rear diff. I believe it not easily visible with the diff installed, so you'll need a mirror or a camera to get a good view of it. The updated #'s are posted all over this site and LS1tech.

Or you could get a dealer to run your vin to get the GM service history of the car. I believe any GM dealer could do this for you. My local Cadillac dealer did mine for free.

Houdini
06-21-10, 07:37 AM
If you do some more research on the forum I think you'll come to the conclusion that it wouldn't be worth it to mess with the pinion brace or wheelhop kit. An axle or two should do the trick for you.

PISNUOFF
06-21-10, 09:01 AM
Go to a dealer and ask for a printout of the warranty history. Or become a supporting member and get one on this forum. Or look at the cooling fins on the back side.

Civardi
06-21-10, 03:59 PM
original is on the top upgraded on bottom.

http://i273.photobucket.com/albums/jj202/Civardi/04-05rear-06-07rear.jpg

smbstyle
06-21-10, 05:10 PM
Go to a dealer and ask for a printout of the warranty history. Or become a supporting member and get one on this forum. Or look at the cooling fins on the back side.

I dont really see a difference in the cooling fins....

i tried to upload a pic but it wont let me b/c of my post count.

http://thumb9.webshots.net/t/76/76/6/57/89/2162657890086116169hcZHTR_th.jpg (http://rides.webshots.com/photo/2162657890086116169hcZHTR)

smbstyle
06-21-10, 08:10 PM
EDIT: looked at the bottom pic and saw that the upgraded diff has a small square notch at the bottom right of the diff and mine has that as well. looks like I do have an upgraded diff!!!! wohoo!! :worship::)

I would appreciate if someone else could look at my pics too as well to confirm. Thanks guys!! This site has proven to be very helpful!

JimmyH
06-22-10, 06:38 PM
yes, it is the upgraded diff

smbstyle
06-22-10, 09:25 PM
wohoo!! Looks like I can cross off upgraded axles and wheelhop kit off the to-do list!! thank you!!

JimmyH
06-22-10, 10:16 PM
The upgraded diff is going to do nothing for wheelhop. It's just a tad stronger, and less prone to hypoid gear whine. It does not alter the performance one iota.

c4ss
06-22-10, 11:30 PM
:yeah:

PISNUOFF
06-23-10, 08:26 AM
wohoo!! Looks like I can cross off upgraded axles and wheelhop kit off the to-do list!! thank you!!

You can maybe cross off exploded differential casing only. I had to get a set of GForce1320 axles to get rid of most of my wheelhop.


The upgraded diff is going to do nothing for wheelhop. It's just a tad stronger, and less prone to hypoid gear whine. It does not alter the performance one iota.

Mine has always whined like crazy, from day 1.

JimmyH
06-23-10, 12:09 PM
My original diff started whining a little at 3000 miles. By 10000 it was howling. So I took it in to get the diff oil changed, and they decided to replace the carrier with the 08 diff. At 18000 miles when I sold it, there was not even a hint of whine. And I was harder on that diff (especially after the HE axles) than I was on the original.

Castro
06-23-10, 03:40 PM
I have the upgraded diff and it's loud as shit. I'm hoping heavier gear oil when I install the axle will help. Then trying an x pipe/muffler delete to help mask it.

JimmyH
06-23-10, 04:12 PM
they probably did not use the correct fluid.

bolide
06-23-10, 05:49 PM
In the pic posted by CIVARDI, the upgraded diff. is the TOP one.

JimmyH
06-23-10, 08:06 PM
Yup, he is right. I went back and checked, and the top is indeed the original diff. It has been a while since I looked at these pictures.

So, sorry OP. You have the original diff (04-05).

Castro
06-24-10, 11:08 AM
they probably did not use the correct fluid.

I was thinking the same thing, it was done under warranty before I bought it so I have no way to tell. Do you think swapping the fluid at this point would help, or is it permanently damaged?

JimmyH
06-24-10, 07:50 PM
I am no expert, hopefully someone who is will chime in, but I know there are clutches in there that can get damaged if you don't use the friction modifier.

Changing to the correct fluid is not going to do any harm, that's for sure.

smbstyle
06-24-10, 08:32 PM
DAMNIT. Oh well.... looks like i'll put the axle back on the list....