Personally, I like the Delvac 1000 15W-40. Shell Rotella T is pretty popular, as well. 15W-40 is a good weight for general, all-around use. It has to be API CJ-4 diesel oil - don't use regular engine oil for gasoline engines in a diesel.
15W-30 or 15W-40 diesel oil is generally used as an all-around engine oil. Specific oil for diesel engines must be used. Any 2009 or newer engine (in the US) must use API-CJ4 low ash diesel oil.
semi synthetic or can use full sytheyic
Most diesel engines are OK with 15W/40 semi synthetic oil For the exact grade recommendation you need to state make, model, cc and year of the vehicle,
There are available many semi- and fully-synthetic oils which are formulated for diesel engines.
Rotella 10W40 is probably the most popular. DELO probably has the best base oil but the additive package isn't as good as some. DELO is an acronym for diesel engine lubricating oil and was the first oil designed specifically for diesel engines. My personal favorite is Mobil Delvac.
well what kind of truck and what engine?
No you can not use gas engine oil in diesel engine oil because processing of diesel engine is different from gas engine oil. If you use this then it damage your vehicles.
Gas engine 10w30 Diesel engine 15w40
It takes a recommended diesel engine oil. Ask your dealer or car parts store.
mobil 1 0w 40
10-w-40 semi synthetic
NO, do not use diesel oil and a gasoline engine.