Isuzu Repair: stiff reverse gear, inhibitor switch, cold engine

Question
QUESTION: i own a isuzu frontier 4x4 2001 model. all of a sudden it's difficult to select reverse gear very stiff

ANSWER: Does it whine or grind in reverse? I would suggest looking at an inhibitor switch problem. Also does it have trouble starting sometimes?

---------- FOLLOW-UP ----------

QUESTION: no there is no whine or grind , no problems starting up. the other gears are fine. no difference in selecting,hot or cold engine.

Answer
Well my first guess would be you need to check and lubricate your linkage. It could either be seized or in desperate need of grease. Or an obstruction could be the reason as well. Bad cable(starting to separate... but not likely) If you need anymore assitance though don't hesitate to ask okay?