If the part is under warranty, I would consider making an appointment with the dealer 300 miles away, hauling it in and go spend the day doing something interesting while it is repaired. The dealer's cooperation in making the appointment and putting a mechanic on it as soon as it hit the parking lot, as well as having the expected (and unexpected!!) parts in stock so the was a painless repair, would determine my future purchases.
I am a reasonably capable mechanic and have no issues changing a seal. My reasons are what happens if you get it torn down and find an axle that had a casting defect which will just continue to cut the seal lips, or a bad pinion bearing which is allowing the axle to flop around causing the seal issue. My point is, see just how good the dealer is when it comes to working with you, at no risk to you, except for a shopping trip with your bride that might cost you more than $250!
I guess 300 miles isn't a big deal to me, since I routinely do twice that every day as a truck driver.
David from jax