What is the best way to check the levels in the diff’s? I know where to check, and what level they are suppose to be at, but how can you tell what level the oil is at? Can’t see anything in that small hole and my finger is to big……I recently had the oil in the diff’s changed at the dealer and today had a small bit of oil on the garage floor under the drain hole. A very small amount. Put my finger on the drain plug and it was wet but not dripping. Just want to be sure.

Thanx