Took the filler plug out and noticed the fluid was foamy (small air bubbles). This was just after I drove the truck. Is this normal?

Mark

 

Also, the level is even with the fill hole. I changed the fluid to Mobil 1 synthetic about 10,000 miles ago.

Mark

 

to my knowledge this is normal. mine is the same way and any other diff i checked right after it was on the road was the same way. When you check it always do it cold or always do it warm. this give you an idea if you are loosing any to bad wheel seals because the level should always be the same cold and should be higher hot. if you can understand this, i wasn"t born to type

 

What you found is very normal.

You may want to check it in the morning, or after it has sat for a few hrs so you know it's ok.

 

Well, I decided to take a little fluid out to get it below the fill hole. I stuck the tube on my little hand pump in the hole and down into the fluid. Guess what happened next? I started pumping fluid out and the tube fell off the pump and down it went to the bottom of the pot. Couldn't fish it out so I pulled the cover, drained the fluid (which looked fine) and will be putting in new fluid tonight. At least there will be new stuff in there now! Now I just need to decide if I want to put synthetic or regular back in.

Mark

 

Definitely synthetic!!!!!

Foamy is bad, Some air is normal for regular driving but if youv'e got Latte for rear juice then either A. you drive short track competitively or B the additives weren't added.
The oil's supposed to have anti foaming agents (usually silicones) to reduce the air entrainment. Remember air doesn't cool or lubricate as well as oil.