94 LeSabre Transmission Problem

Shifted my LeSabre into OD/D this morning and nothing. Park, Reverse, 2nd and 1st gears worked. No previous warnings of transmission problem, i.e. noise, grinding, leaks, etc. Don't know if GM set up this vehicle to allow it to use 2nd or 1st gear (creeper gear?) in an effort to help move the vehicle out of harms way or not. Any thoughts on what is happening is greatly appreciated.
Thanks, Kevin

First things first, is the transmission oil level okay. Remember the level should be checked with the car running and in park.