Front Dif fluid low.

I just did a front axle & bearing swap on both sides. Pain in the butt though i got it done. My question is: how far can i drive it if it's about 1/2qt low? My allens are at work, not at home where i worked on the truck making it difficult to get the fill plug open. The vehicle was at a pretty sharp incline (clearance ground to tire approx 12"). I don't think i lost more than a 1/2qt pulling both axles but it's hard to tell. It's about 50 miles through the mountains to where i work & i have the gear oil (2 qts). Just wondering if it's possible to drive the truck or if the diff needs to be completely full to avoid risk of damage?

 

You'll be fine, the front diff isn't doing anything without it being engaged (just axles are spinning, no carrier action), so 2WD regular speeds will be fine for 50miles

Edit: The carrier spins, but doesn't have any load.