An NPR diesel uses a 15w-40 weight oil in most applications. Gas engines use 10w-30.
98 Isuzu npr oil capacity
I have an Isuzu NPR 1992. The oil capasity is 12 quarts.
12
11.5 qts
Most of the Isuzu npr trucks holds 6 and a half quarts of transmission oil.
10w-30
15W40
6 qts
20
I use 15w-40 amsoil in my trucks with no problems and it takes about 3 gallons.
The Isuzu NPR uses 85W140 gear oil in the differential and you can use chevron starplex 2 grease when greasing the chassis.
9 quarts