My passenger side axle has been knocking for about a month now and has gotten progressively worse over that month or so. The odd thing is it will only knock if its in gear. I just got under the car to change the oil and looked and saw the boot on the passenger side was torn at one of the smaller diameter sections of the boot.

Im sure it should be replaced since its been so long, but should I replace both axles or just the one? discuss.

 

bump after yesterdays food coma.

 

just replace one