So thanks to the api specs, they have made oils pretty uniform, so no need to stress, there are less differences between oils then every before. We are currently in the gf-5 oil era, and soon to be in gf-6 oil era, and most people aren't looking forward to that as the direction oil formulations are taking serve modern di engines better then older applications like our hemi's.
The issue with the market place is to get an api donut, you must adapt the one size fits all standard, and clearly that is a grand bargain and may not serve hemi's well. If you find a good oil and the truck sounds good on it, you might want to stock up, because when gf-6 drops those oils will cease to exist.
Ram forum is pretty educated on oil, the poll of most used oils are Pennzoil synthetics number 1, m1, amsoil and redline top off top 4. Redline's usefulness comes if you have lifter tick, if not you might want to go with any of the other three, I like Pennzoil 5w30 myself, the most used oil for rams.
Read moly basics, this is where it gets a little complicated. gf-5 does not limit moly, so that is one element that you might look for. All of those 4 choices have moly, redline has the most, amsoil the second most, and pennzoil and m1 average moly. High moly oils also include shaeffers, qsud, rotella truck and gas, and others. You can look at pqia and search uoa's and voa's for moly levels, or just ask if you had an idea about an oil.
Having said all that, I'd look hard at Pennzoil Ultra Platinum 5w30, named "PUP", If you are one of those must use what the dealer says, try 5w20 PUP. It likely have more detergents then most any other oil and no doubt on our uoa thread and every uoa thread this oil consistently produces the lowest wear numbers.
