After replcing the rear diff bushing, the jerk that you would feel after shifting is gone. I replaced motor mounts on Saturday and the bushing on Sunday and only drove about 40 miles in between. I drove it enough to know that there was still slack in the drive line that made it hard to shift smoothly. The stock bushing didn't look worn out but it made a difference. I used the CS tool and it worked pretty good, you are not getting it out with out a special tool.
CS bushing, watch the exhaust bolts at the cats, mine snapped on the left side (Might want to try a little heat on them first, although mine were stock and had never been off since new, def use some good lube if you have no heat). Car tracks in a straight line now, always wanted to pitch right. And NO CLUNK... lol.
I replaced mine with a CS about a year ago but somehow the three diff bolts did not tighten all the way. I drove it until this past weekend thinking I had a bad driveshaft. Got under it to swap the shaft & put in CS motor mounts, realized this & just torqued the hell out of those bolts. Now with that & the mounts done this car feels totally different. More planted. I can shift with no worries.
Just a recommendation: get the mount bundle from CS. Motor mounts, trans mount, diff bushing & diff block. You won't be sorry.
I hear that the CS transmission mount causes a ton of noise/vibration issues. I wonder if those issues could be correlated to CTS-Vs equipped with short shifters. Was planning on doing CS differential mounts, UMI motor mounts, and leaving the transmission mount alone unless there are shifting/driving advantages to be had due to poor alignment caused by the OEM mount.
__________________ 2006 CTS-V - 422 RWHP/383 RWTQ/3795 lbs - Complete Mod List
- G-Force 9" IRS with PST 3.75" carbon fiber driveshaft and 35 spline axles
- Strange Engineering S-Trac with Pro Iron case and 3.50 ratio
- KW Variant 3 with Swift 120/160 springs, Banski RSMs, Custom FK LSMs
- 5-lug 19x11/20x12" Forgestar F14s, KRC adjustable power steering
- RacingBrake 355/365mm 2pc rotors, ET800 pads, CTS-V2 calipers
- McLeod RXT, Custom McLeod 1373, Comp TRuTorq L3 cam
Mine was shot to hell, you could feel / hear the diff rocking while shifting. I took the easy route though and paid a shop to replace the bushing and add the diff block. It made a huge improvement. It felt so much more planted taking off from a dead stop and I was able to get a tiny chirp out of 4th gear.