I'm selling a rear differential that came from a 2004 Cadillac CTS with 116,000 miles. I only replaced the differential to put in an upgraded unit. This differential does NOT make any noise or whine. This unit is from a vehicle with RPO code GU6--in other words, it is NOT a limited slip differential.

This differential DOES work in 2005-2007 vehicles, even though the GM parts interchange manual does not say so.

For proof, see the image that I took below when I was swapping in a newer differential. The differential to the left of the image is a 2005 model. The casting is different, but the suspension mounting points and driveshaft coupling are identical and will bolt up perfectly to a 2004-2007 CTS.

Note: for some reason this ImageShack picture doesn't want to load regularly. You might need to reload the page a few times for it to show up.

$199 local pick-up in Chicagoland area
$299 shipped