Here is a procedure I found and seem to recall using the same technique before on a T31
You must use ORIGINAL KEY to start procedure
1. Sit in car lock all doors with power “switch lock on driver side door”
2. Using ORIGINAL key insert and remove key till doors UNLOCK within 8 seconds, usually insert and remove six times
3. Turn ORIGINAL key in ignition to ACC position (Do not start engine)
4. Lock all doors with “power door lock switch on Driver side door”
5. Press lock or unlock on NEW key this will match them up, if you have another key press lock or unlock as well, it will be programmed all keys to the same code.
To exit program mode, turn the ignition OFF. UNLOCK the door using the driver side switch. Test fobs