quedogf94,
You did not list where you live, so the following info. may not apply. I have a similar problem that I spent all spring working on. I live in what is considered zone 6 according to the literature that I have read. The yearly temperature low is -10 to +10 degrees F. My problem is that this past winter was a warm winter for my area with little snow fall, but with a lot of rain fall during the winter. The grass on the front slope on the side of my house washed out, so I spent a couple weeks moving dirt from another portion of my land to the washed out area. I then used a PTO tiller to till the dirt. I fertilized and planted grass in the tilled soil. The grass grew well until the end of June. My area is having a rain shortage along with hot weather so my new grass has now turned brown.
I am now going to place a border of football sized rocks around the entire area. I am then going to place junipers at the bottom of the slope and around the edge next to the wood line. I am also going to plant junipers across the center of my slope which is 50 yards in length. The center line will be approximately 20 yards across. I have used junipers and rocks before to stop soil erosion in other areas. Junipers will live almost anywhere and they don't require a lot of care.
I also had the same trouble with the ruts in the washed out area. I tried to patch the ruts but this method did not work for me. This is why I resorted to the above. Good Luck.