4x4 Auto

[Einstein376]

I wondered if anyone has noticed any MPG difference between having the truck in 4x4 auto vs. 4x2? My GMC was a couple of MPG lower in auto and I wondered about the RAM.

Thanks,

Jim

 

[jimchi]

I was reading in another thread that in 2WD mode, there is an axle disconnect that is not engaged. This means the front wheels are the only front drivetrain components that are turning.
In 4WD AUTO, the disconnect is engaged, meaning that the front wheels are turning the front differential and front driveshaft. This would contribute to a reduction in fuel economy, even when the transfer case isn't sending power to the front axle.

That's my understanding and I could be way off, I haven't confirmed this with any literature.

 

[Einstein376]

That certainly makes sense.