I'm have a question about the front 4x4 actuators. What do they do or what is their purpose? They do not disengage my front drive shafts from spinning or should they? My truck seems to have more drag on it now, and I have lost 1.5-2 mpg for highway driving. The dealership just replaced my passenger front 4x4 actuator. Since then nothing has felt the same. Thats when I noticed the front drive shafts dont disengage on either side. Should they? Thanks in advance.

 

Yes, in 2wd neither the front driveshaft nor both front axles should be turning. If the axles are turning, your hubs have no vacuum. Vacuum disengages them, lack of vacuum engages them for 4wd operation.

Take it back to the dealer, they neglected something.

 

Thanks a bunch. I knew something wasn't right. I'll comment back after I get it fixed.