Shaft clearances / bearings
They measure only on the pinion bearings. The value should be 0.1 mm per every 100mm shaft diameter. The limit is 3 times that value.In cases of insufficient clearance, the risks are related to the expansion observed start. The shaft may expand more than the bearings. The result is the complete destruction of the bearing.
In cases of excessive backlash, vibration which is based on the backlashes of the line tends to be more important. Excessive amplitude may also cause damage to the bearing but also in the kinematic chain.