Best Way to go down a hill?

I'm wondering what would be the best way to go down a hill with an 8%
grade within my cars circumstances? The brakes are semi-good, when
coming off a higher speed they do shake a little. The transmission however
is going bad to the point where I have no choice but to use overdrive at all
times or else my car won't shift properly, even with overdrive on it still doesn't
at times but not as bad. I just need this car to last me one more week before
we can get a new one, however with husbands new job there is a steep hill
im concerned about mostly with my brakes.

So what would be the best way for me to maneuver the car through these
hills using overdrive without having to apply alot of brake at times? 45 mph
down the hill, with a traffic light around the bottom. Would it be safe to
downshift into a lower gear with the overdrive on? If so what should I use?