Yes, it can be done, but is a real bear on your back. You will have to drop the exhaust out of the way, drop the heat shield between the exhaust and driveshaft, remove the driveshaft from the back of the trans (leave it connected to the diff and lash it up out of the way off to the side), and then disconnect the shifter. Prying out the old seal is difficult, and getting the new shifter joint back on the shift rod is difficult as well. If you're an experienced DIY mechanic, then it's straightforward. You will need new bolts for the driveshaft - one time use angle-torque-to-yield. You only have to remove 3 of the 6, I usually pull the guibo off the back of the trans output flange instead of pulling the driveshaft flange off the guibo. It gives you more clearance to work up there. You can also drop the back of the transmission down if you need more clearance. The engine and transmission balance on the engine mounts, so it may not come down when you pull the trans mount bracket off the chassis. Gently push up on the front of the engine with a floor jack to get the back of the trans to drop down.
E92 335i/6MT Dinan Stage 3: intercooler, oil cooler, intake, flash, exhaust, LW dual-mass flywheel.
Vishnu PWM methanol custom trunk mount, Diffsonline 3-clutch Salisbury custom diff, Ohlins Road and Track coilovers, Vorshlag camber plates, much more...
E28 M5 w/ buncha stuff, R171 SLK350