Gary,

Our coaches are similar in year, and I assume similar in function. I can definitely feel the jake, but as others have mentioned it's much more effective when used at higher RPMS.

ON my previous bus, after a DD service, it turns out my jake wires were not connected into the motor, and believe me, going down any hill without a jake is a scary thing.

If you can't find a hill to verify, try to find a tunnel, or concrete wall nearby that you can open your window and listen. You should definitely here AND feel the jake.

Ray