1 - The reservoir in the picture below...is it a brake fluid reservoir? I know the one behind it to the right is the master cylinder but what's the other one??

2 - Should I be concerned with the other picture, front diff?, Not wet or dripping but......?

Thanks in advance!!

 

The one your arrow is pointing at is the brake master cylinder, the smaller one behind it is for the clutch.

On the diff, you have a seal going bad. Nothing new under the sun there. Check the fluid level, make sure it's up to snuff, fix it when it's warmer outside.

 

Is there another name for the seal? My manual doesn't have anything on a seal. Also, is it hard to do? Thanks!

 

Pinion seal.
Is it hard? Look in your manual and youtube to see what's involved.
Most auto parts stores have the puller you'd need as part of their loaner program.

 

 

Would this be the same for the front? Thanks!!

I'm also wondering how the fluid went towards the front of the diff?? How does that happen?

 

Process is the same. And the fluid is running to the lowest spot.