Yeah, the driver side 8.8" conversion axle is a tight fit. I found that a couple years ago when I had a torn CV boot and had to pull the axle to get that fixed.
I ended up unbolting the driver side rear diff mount (where the CS bracket bolts to the rear subframe), loosening the passenger side mount, then rotating and pivoting the diff so I could get the axle in. Quite the pain in the ass, even with the car on a lift and another guy helping me try to finagle everything together.