Which Oil Grade do I Need?

Follow the owners manual and you can't go wrong

I wouldn't worry about it and use what ever you want, seriously.
When have you ever heard or not only an oil related engine failure, much less a viscosity related failure.
I have vehicles and toys with various viscosity and or synthetic oil requirements of all kinds.
I think my total cylinder count is around 60 right now from powersaws and mowers, boat, car, trucks, old and new.
EVERYTHING gets 15W-40 (I'll lower that here in AK this winter in the trucks) diesel rated oil. Buy it on sale multiple cases at a time. Hasn't been a problem for lotsa years.

I would recommend sending an email to ram & ask them. I have found them to be pretty prompt in giving answers.

Maybe this will help:

Motor Oil 101

darsben wrote:
The answer is in where you go and how you travel. Since the 5W only comes into play in cold weather if your truck never sees cold weather such as in S. California, Florida or south Texas then the 5 will probably never come into play.
The 30 is okay all the time as it gives a higher viscosity at high temps. Remember we are talking engine temp not outside temp. So while the engine may start out at ambient temperature it will eventually warm up to operating temp. If you are towing the temp may go a higher than when not towing that is when you want the higher viscosity. The owners manual is the bible for warranty work so stick with the 5w30.

The 5 comes in every time you start it.

The only reason a manufacture recommends a 20W oil is for mileage and only for mileage.

Do what you want but I would use the 30W. :)

I would go with 5w30 all the time.

The answer is in where you go and how you travel. Since the 5W only comes into play in cold weather if your truck never sees cold weather such as in S. California, Florida or south Texas then the 5 will probably never come into play.
The 30 is okay all the time as it gives a higher viscosity at high temps. Remember we are talking engine temp not outside temp. So while the engine may start out at ambient temperature it will eventually warm up to operating temp. If you are towing the temp may go a higher than when not towing that is when you want the higher viscosity. The owners manual is the bible for warranty work so stick with the 5w30.

I'd use the 5w30.

You need to understand what the numbers mean to make an informed decision.

The 5 means the oil "performs like" an SAE 5 grade oil when it is at 40*C.
The 30 means the oil "performs like" an SAE 30 grade oil when it is at 100*C.

The oil has a higher absolute viscosity at 40*C than it does at 100*C as any oil does, but multigrade oil is less so.

Long story short, they feel they need the added protection of the 5w30 for hauling heavy loads when the 5w20 will be too thin. If you run 5w30 all the time, you will sacrifice a miniscule amount of fuel economy.

I'd discuss it with the service manager at your local dealership. I had the same quandry with my '13 Ford. My service manager conviced me to to with the lighter viscosity oil.