Replaced gear box

Mario

Hi, got a Holden Frontera Isuzu 2000, automatic and decided to change over the gearbox, got one from same model and year, gearbox fitted well, only electrical connections were different. Problem is, starter motor now will not engage.
It sounds like if it's hitting against something, but that can't figure out what it's is. Before change over, there were no problems, is possible that the starter will hit into the gearbox? Please note, (I'm just an amateur, not a mechanic)
Thank you

PF_Flyer

The vehicle is 19 years old. Could simply be that an issue with the starter cropped up coincidentally. Are you able to get the car into neutral when you try to start?

Mario

Yes, neutral will engage with no problem.