Just a WAG but IIRC there's a cold engine temp sensor wire that goes to the tranny which prevents going into OD when the engine is still cold (helps warm it more quickly too).

Off Roader
98 Montero with the Winter Package
89 Montero minty clean and reserved for overlanding trips or Cars and Coffee events
96SR (3.15:1 xcase, 35's) gone to the rust gods
96SR Build Up Thread
Old web page
Old web page