I’m no expert on the matter but I’ve been lurking a while. Personally I’d check with the gear manufacturer for a recommendation.
Next up, grab some coffee and read this:
Do read all the pages at the link that was given to you in the last reply..
YES, you do want to change the gear oil out and don't wait a long time to do so... You will want to drain and carefully look over the drainage and what is in it /might be found on the magnetic drain plug...
You will get different answers when best to do this first drain and check.... some will say 2,000 miles others will say less....
DO use Synthetic. What to use fluid wise... hints on doing the deed, etc., can be found at the thread mentioned.. Remember, always be sure you can get fill plug loose BEFORE you drain the fluid..