Morning after a 3+ hour drive truck started to make whining noises. Noise comes from driveshaft area, towards the back near the diff. Sound is at any speed/gear, gets higher pitched the faster the shaft spins. I will try to upload a video of it.
I'm having the same issue in mine.
What would make the differential fluid run low? I'm not very mechanically inclined, so I will probably have to take mine to a mechanic, and I would kind of like to have an idea of what's going on before I get in there.