The platform that the turret crew rode on was fixed to the hull, not to the turret. When the turret was slewed off center, the gunner had to do contortions to service the 76mm. In other tanks, when the turret rotated, so did the turret crew.
Also, the transmission was MASSIVELY prone to breakage. I read that they would routinely deploy with a complete spare transmission chained onto the rear deck.