The maintenance minder is incorrect on these 3rd gen CR-Vs. There is a Technical Service Bulletin to change it at 15K or 20K miles (I cannot remember which, search the CR-V forum if you really need to know). If you wait too long, the rear diff begins to engage while driving/turning and you'll feel vibrations.
If you think you are having problems, the TSB said to put the car in reverse and turn the steering wheel all the way to the right and drive in circles. Repeat this to the left, also. If you feel the rear diff grabbing, you need to flush the diff with thee fluid changes. This will correct the grabbing and vibrations.
If no grabbing/vibrations, do a single drain and fill.
I 1x drain and fill my rear diff every year or 15K. I use the Honda Dual Pump 2 fluid. It takes a little over one quart, so buy two. It's also helpful if you get a pump that fits the top of the bottle. They're pretty inexpensive and worth their weight in gold for this job.