[1Nebel0]

I have a 2007 one ton duallie and will be putting a higher capacity cover on. The dealer wants $27.95 a quart which is rediculous...I want to use Amsoil 75-90 oil.. do I need to add the modifier or is the syn enough. The truck has posi rear end.. The dealer said their fluid doesn't need the modifier...I have little confidence in counter people and put my faith in this forum. I will use what ever the group feels is good oil...just don't want to buy the OEM oil(8 quarts) at $27.95 a quart ever 15,000 miles. Thanks for all the great insights always...Steve..