Timing gears jumping

[Morties2019]

Hi all
I am driving an Isuzu pick-up with 4jb1 motor. On two occurrences it just shut down and with further inv9I have found that the timing gears have jumped. Not every time on the same gear. The gears teeth looks visibly to be ok . The motor have seen 370 000 km.
Please advise on what could be the problem.

Regards
Andrew

[geeves]

Is this the gear or belt drive version? Belt will have a plastic timing cover.
If belt options are loose worn or wrong belt
if gear worn gears or the pulley slipping