A question that is often asked, and for good reason, is do I need a two or four wheel alignment? With pickup trucks with a solid rear axle then it only requires the front two wheels to be aligned. Even if the truck is a four wheel drive, it still can only receive a two wheel alignment. The reason for this is there are no adjustments for the rear wheels, the wheels are set solidly in place and do not require any adjustments.
Cars without solid rear axles generally will need all four wheels aligned as there are adjustments at the rear wheels as well. Wheel alignments on these vehicles consist of setting the rear wheels and then setting the front to match the rears.
Cars with independent rear suspension will generally require all four wheels to be aligned.