Question
WE HAD SOME DOZER WORK DONE AND I HAVE A STEEP HILL IN THE BACK OF MY YARD.  I HAVE CLAY DIRT! I SEWED MY HILL IN RYE GRASS AND PUT HAY ON IT TOO KEEP IT FROM WASHING THE SEED OFF.  I WAS SO HAPPY IN THREE DAYS I HAD A BEAUTIFUL GREEN HILL.  SO I SEWED THE BOTTOM OF THE HILL IN MY BACK YARD WITH THE SAME KIND OF GRASS BUT I BOUGHT IT AT A DIFFERENT STORE.  WELL THE GRASS ON THE HILL DIED ABOUT A WEEK LATER.  NOW THE OTHER GRASS IS DYING ALSO.  HELP WHAT SHOULD I DO.  IT IS GETTING CLOSE TO WINTER AND I DON'T WANT THE HILL TO WASH IN MY BACK DOOR.  THANKS FOR YOUR ATTENTION.          BRENDA

Answer
Hi Brenda;
Nothing will grow in clay soil except weeds. Water can't get through that clay to get to the roots, and the roots that do sprout aren't strong enough to punch through clay.
You have to till in some soil emendments to loosen up the soil.
I would till in some bark mulch to loosen it up, add some corn gluten meal to feed, help control some of the weeds and add nutrients and control fungus that will be a problem in the spring. Add enough bark mulch ( cedar bark mulch helps repel a lot of insects) to cover about 3 inched deep, and corn gluten meal at the rate of 40 pounds per 1000 sq.ft. of lawn.
I would water it to get out air pockets, and maybe e\ven roll it to get more out, then I would lay sod.
You don't really have enough warm weather left to get grass to come up from seed and get established. The sod will anchor the soil a little better, but you really need some kind of retaining if that is a steep hill, and soil is likely to wash down.
Just somew large boulders for a retainer wall might work well enough.
You really need the deep roots of some sturdy trees or large shrubs to anchor a steep hill of soil.
Charlotte