Started having a problem with my 08 Tl type-s about a year ago and am finally getting around to looking at it. The car runs and drives great, but for some reason it won't shift into reverse or past 3rd gear. Even after sticking it into manual mode it won't let me shift gears whatsoever... Have read a few articles and am wondering if it could be the shifter forks within the transmission. Open to hearing whatever other ideas anyone might have. Had the P0741 code pop up on the navigation multiple months before this happened - not sure if that has anything to do with it.

 

It has automatic transmission, right? Auto trans like this one doesn't have shifter forks.

In a very brief and not entirely correct summary; gears are selected by electrically operated valves that let transmission fluid flow to the clutch packs, and that fluid pressurizes kind of a piston that squeezes the clutch packs, selecting the gear.
Gear not selected -> Solenoid not energized and closed and doesn't let fluid flow -> No pressure at the piston -> Clutches are not squeezed so they can slip, therefore acting as neutral / not engaged.

Since car doesn't allow you to select the gear, I'm assuming car's computer knows something is wrong, and it entered sort of a limp mode.

So first thing is to make sure transmission fluid is ok, second thing is to connect the scan tool and read what codes are present / current / pending.
After checking that report back.

 

Yes, it is an auto trans. Thank you for the information. Finally got the chance to check, and the code is P0766 Shift Solenoid D Performance/Stuck on. There’s also a separate code for a rocker arm actuator system stuck on bank 1 (P2647), but I think that one’s been on for a long time. Is the P0766 a relatively simple one to fix? Just want to assess the costs and time that might be involved.
Thanks!