Prado Somthing Weird

Hi all, this is very hard to desrcibe but here goes. VX Grande, V6 petrol,Auto, I have been told its common, have also been told its the rear brakes but I dont think its brakes. After I have stopped, when I reaply (start moving again) the accelerator its like a double movement. Its like a bush is worn in the suspension it feels to be coming from the rear, theres no definant clunking sound as such but you can feel it as if when you have stopped then when you accelerate like the diff moves a centimetre or so (just my way of describing)). Now I have had two mechanics look at one best mate who works for toyota who says it is common he has had the odd one or two do it, the other mechanic is also a member on here. Now the mechanic on here had it up on his wheel alignment ramp with his junior mechanic at the wheel running it forwards backwards while he was lying under neath seeing if there was any movement any where.Nothing, he checked all the bushes etc no movement in anything. So would it be any thing to do with the tranny, worn shocks (would this cause it) or any thing else that would be causing it. I know you people on here are a wealth of information so hopefully some one with a prado might have felt this before. If it a common thing as my mate says it is I will live with it.The vehicle is super smooth no vibrations when driving etc. Very weird feeling.Has been doing it since I test drove it but as said mate said its one of those things some do it some dont. He has also felt it in cruisers as well. Now I'm not knocking either of these mechanics for there expertise in the field as they know a sh#t load more than I do about cars but just thought some one may know what it is. The vehicle has never been smashed totally stock standard as in rig pic. Any thoughts ??? Regards Steve M