Cadillac CTS-V - new trans installed but hard to shift and drivetrain whine presists

I have 07 V with 72k and took it in for drivetrain noise. I figured diff but dealer instead replaced trans with new unit and also replaced clutch slave and clutch switch as they found it hard to shift when taking it for test drive. I get the car happy it has a new trans and slave but its really hard to shift gears now. Shifting up to 5th or 6th and back down to 5th from 6th especially takes a lot of force and precision. I have a pisnuoff modified stock shifter and bushings. Also to boot the drivetrain noise is still present. They agreed to look at again on Monday after waiting 12 days for a new trans to arrive and be installed, but any ideas what either of the issues could be?

I did some searches and plenty of people state their diff's whine which is why I took my car in to begin with but could a motor mount cause this sort of issue or maybe the clutch has finally given up. One of the motor mounts was changed about 40k ago and afaik its the original clutch. I am sure the clutch is due but are certain gears harder to find as the clutch starts to fail?

The drivetrain noise is from 2k-3k rpm in 4th-6th gears and also when engine braking through that rpm range, can hear a higher pitch noise coming from either trans or further downstream in the drivetrain.

I know that bad mounts can cause shifting difficulty... I had problems before I changed mine out. A bad clutch can also cause the same problem... air in the system can do it as well you might try bleeding the clutch. As far as the noise... without a sound clip it's hard to say other than the diff is most likely the culprit.

I guess its possible they didn't bleed the clutch right, although unlikely.

Update: Dealership is ordering new diff but says small amount of whine is normal. Also states new transmission is tight and will take some time before 5th 6th gears can be accessed easily in all situations and motor mounts were said to be ok by dealer.

I suspect the clutch is dragging but will give it some time. I have planned to do a ls7 clutch at some point this year but if this thing doesn't loosen up in the next few weeks my hand will be forced to go ahead early with it.

Update: New diff installed today will update later tonight if its quiet.

Solved: Serial 0006450001210E installed (assume this is gen4) and its quiet. I could always get noise around 2-3k in 4th/5th gears but now all I can hear is the stump pulling ls2.

Awesome. Glad you got her fixed up.