Grinding while accelerating

[rfuree11]

Grinding while accelerating- Driveshaft?

So I went on a run a few weeks ago. Nothing too crazy with a few minor water crossings. I don't think any water got into the diff, but I'm not 100% sure. I've driven maybe 1-2k miles since and just got done with a highway trip and when driving on side streets, a new noise has popped up. When rolling from maybe 5mph, I get a grinding noise from the rear when I get on the gas. What are the odds this is my diff failing vs some random bearing going out? I don't really notice any vibration or clicking.
It sounds almost like rusty brake rotors getting cleaned off, which is why I'm leaning towards bearing.

 

[rfuree11]

So I think I may have found the culprit, but have no idea if my theory makes sense. I crawled under the car and the driveshaft has thrown a LOT of grease. Maybe the seal failed? Would that cause it to make a grinding noise? To give more insight as to what noise it makes. It comes somewhat intermittently. I can recreate it very easily by giving it a little bit of gas then keeping the speed steady. If I let off the gas at all, it seems to go away. Here's a picture of the slip yoke:

 

[rfuree11]

Well, it doesn't appear to be the prop shaft. I lubed it up this morning and the noise is still there. It's going to the dealer Tuesday. Hopefully its covered under warranty. I'm not in town right now, so I can't put it in the air to track down the sound. I'm thinking pinion bearing, but it seems tight when I wiggle the driveshaft.

 

[jonathansdotson]

Any updates? I'm having a similar noise as of late.