Was wondering what oil to run in a 933 G with a d 320 t in it 30 wt detergent or 15w 40 thanks in advance                                   Chris

it depends on the ambient temperatures you will be running it in? if really cold the 15w 40 is beneficial

just run a multi grade we have 38 40 degrees celcius in the height of summer and that what we use. most machinery will run just fine with 15w40 all year round.
another point to remember oil technology has moved on and we arent working these machine hard they are in active retirement not earning a living.

one thing to remember these old girls dont like zinc fortified oils in gear compartments due to the bronze gears and bushings and the chemical reaction that happens with zinc additives and bronze.

simply get a recommendation from your chosen oil company.

It doesn't really get super cold where I live and it will be warm most days I run it  

I don't run my machines much below freezing so i use straight 30W oil in them