My step-daughter has an 03 Montero Sport. She called last night and said it wouldn't crank so the wife goes and gets her.

Fast FWD to today...wife calls me at work and says that my father in law went to check it today and he said it only clicks when the key is turned. Tried to jump start it with no luck.

What say the experts here? Starter? Solenoid? Possibly the transponder key (do they "go bad"...she only has one transponder key so no way to try another)?

Any other issues that I should look for?

 

Do your gauges and lights work? If all you hear is just clicks, it is likely the battery.
If the battery is very very dead, just connecting jumper cables will not work. You need to leave the cables connected (with the donor vehicle running) for some time, in order for the battery to store up some juice before attempting to turn over.
I'd suggest to take the battery out and take it to a part store nearby. They should be able to put it on charger and check to see if it holds the charge capacity.
Good luck

 

Got it going again Monday...it was the starter.

Now, I get to spend this weekend changing valve cover gaskets, intake plenum gasket, spark plugs and seals, and the infamous crank seal orings