1. Verify that the joint shaft is not twisted or cracked.
2. Turn the joint shaft by hand and verify that the bearing rotates smoothly and freely.

Drive shaft
Joint shaft removal/installationMazda 6 Service Manual: Engine Coolant Temperature Gauge (Without Multi-information Display)
Displays the engine coolant temperature. The white gauge indicates that the engine
coolant temperature is low, and the red gauge indicates that the engine coolant
temperature is high and overheating.
CAUTION
If the engine coolant temperature gauge indicator flashes, there is a possibility
...
Mazda 6 Service Manual: Picture Quality Adjustment
WARNING
Always adjust the picture quality of the rear view monitor while the vehicle
is stopped: Do not adjust the picture quality of the rear view monitor while
driving the vehicle. Adjusting the picture quality of the rear view monitor such
as brightness, contrast, color, and tint while dri ...