...it is 1/4 inch thick steel...
Well then, 400# may be on the low side. My bad.
But unless you and your 3 friends are
extremely strong, removing a 400# pallet, by hand, off a standard pickup is a recipe for some major (even life-altering) injuries to man or machine. You
can't just take the total weight, divide by 4, and say "I can lift that!"
Granted, once it's on the ground, getting it off the pallet and wheeled to your back yard sounds do-able.
But please think this through and consult some people with experience in rigging and moving unless you guys are NFL stars. I'm an old weak guy but I have long strong planks,
long pry bars, fulcrums, come-alongs, floor jacks, pipes for rollers and wedges for brakes.
Please have a plan for every move.
You might consider renting a 2-axle Uhaul trailer. That's how I move pianos. They're low to the ground and have a nice pull-out ramp...provided you have a strong enough dolly that will handle this kind of weight on a pallet. Consider wheel diameter and wheelbase so you don't "bottom out" at the top or bottom of the ramp. Then your retailer can load it up
on the dolly and the whole works is strapped in the trailer. (You'll want some beams on that dolly--the 1x4's of a pallet won't take being supported on a small area. )
Let us know how it goes.