Replacing tires on an AWD car

Since your car is part time AWD you can replace 2 as per the manual but all 4 is better. At 50k you really should do all 4.

Are the tires high mileage Michelins say like 70k?

I would be cautious and replace all 4 tires or find a tire that is the same brand and series with similar tread depth on E-bay. I am in the same situation right now with my 2014 Dodge Ram 4x4. I ran over something that did damage to the tread of a tire and plugging it made the tread bulge under pressure. I will be replacing all 4 tires as they have only about 25% tread left.

AWD seems to built with no tolerance for this. I would understand & accept same tire size if it were to be any range of that same tire size stamped on the tire. The tiny variants in tire size by AWD systems is too narrow and are not acceptable, instead of the system (AWD) having allowable tolerances built in, AWD systems currently have allowable damage & cost of repairs built in at consumer loss. Their precision product flawed without regard for real life sent out for consumers to worry about. Its the same as the consumer worrying about if the metal is poured/mixed correctly at the plant. Its their poor decisions not consumers neglect, but engineers neglect.

As a general rule of thumb,with most AWD vehicles you should replace all 4 tires...Note I said most; if it's something like a chevy Astro AWD, you *must* replace all 4 as they have a chain driven transfer case and not some slip and slide viscous device between the axles.