Hi wippster,
Yep. Had three go on my 3320!
Guys at the JD dealer said it was very common for the front seals to go... attributed failure to working in mud, or water with sand or silt suspended in it.
I really did not like to hear this, but was guilty of working in mud, and water with silt.
All were covered under warranty, problem was being out of commission!
DO NOT drive 4 miles without putting lubricant in the front axle--I would not drive at all. If it's gushing out, you could put a gear oil in it for the trip to the dealer... a lot of folks out of warranty do this anyway, and personally, it just makes more sense to me to use gear oil on gears, but...
In talking with the dealer when I traded, I will have him ship me the kit if the problem happens on the 3520, as it is a very simple repair to do ones self, which would save a guy with a 260 mile round trip a whole lot of time and money... not to mention get a look at what's causing all the trouble!
Sorry to hear it...