My truck is 4 wheel drive. Ive used it a few times and havent really had any issues with them. as far as them being vacumed I dont know. I would assume they are since they work off that little knob insted of a shifter like my old dodge. But my ac problem is kinda wierd. if i dont have the ac temp to low and the fan only around the 2nd setting i will get more air out of the driver and passenger vents. If i turn the temp in the 60's and fan all the way up it will blow out the defroster