Questions When one wheel is raised and the other in the floor should it spin freely? When both wheels are raised when one is rotated should the other go same direction or different ? I ask because I bought a Trd mechanical diff From td04 glanza Had it fitted and went for mapping. From reading reviews the car should lock and pull with both wheels However it didn't I nearly ended up in the hard shoulder. I contacted my gearbox specialist and he says this is not right the diff is either faulty or not as described. If I am wrong I will apologise for the mistake, if not I want the issue