99 Mercury Cougar Shift linkage?

My son has a 99 Cougar, V-6, 5-spd. Last evening he was "maneuvering" out of our driveway..in reverse...and backed into my truck :shakehead. No real damage to the exterior of either vehicle. However, the Cougar is now stuck in reverse. Gear shifter moves up-and down...no left-to-right motion. Regardless it does not change gears. I pulled the shroud & foam from around the shifter...I see some linkage beneath it, but as I move the shifter it does not move the linkage that I can see. I read where someone suggested getting a diagram of the shift linkage to find a break in the linkage. Where do you get a diagram? I have a Chilton's repair manual for this vehicle...but see no such diagram. Any suggestions? Am I on the right track? Any assistance you can offer will be appreciated.
Thanks!