We have 1991 international trk with VIN # IHJSCHKM5MH364695 we need to know what motor it has.

How do we find motor by VIN # in a international trk ?

With most late model vehicles, the 10th digit is the model year designation, and the 8th is the engine model.
I don't know if that relates to commercial trucks, but I also don't know why you ask...

What matches here is the model year: M + 1991.
Therefore, I conclude that the manufacturer's engine "model" is also "M"
I hope that helps, at least a little.

Who is needing this info and for what purpose? Purchase, identification, repairs..

Can I engage or disengage my power devider without stopping my truck.

I have a 1991 international tadem truck is it safe to engage or disengage my power devider without stopping the truck.