Jake brake
Ben,
Sorry, I can't help you on the jake brake problem. But I can suggest down shifting your transmission to slow down. By selecting a lower gear to descend the hill you will use your brakes much less. If there is a highway sign warning of a steep grade it will usually have a suggested speed. I slow down to that speed at the crest of the hill and then downshift from 6th to 3rd or 4th gear. I use the brakes only to keep the rpms from exceeding 1800. After a little practice doing this, you will only need to tap your brakes to stay within a comfort rpm range.
Hope this helps until you can get your Jake brake fixed.
Tuga & Karen Gaidry
2012 Honda Pilot