Jake Brake
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Forum Discussion
I'm assuming your 425hp Cummins is an ILS which has an "engine" brake (commonly referred to as a Jake brake) as opposed to an "exhaust" brake (which can also be referred to as a Jake brake). Engine brake has two positions (Hi and Lo as you indicated) whereas an exhaust brake only has one position (on or off) and is commonly found in the Cummins ISB and ISC engines.
It sounds like you have a separate on/off switch and then a secondary switch to determine which position. Does the position switch have a "neutral" position??? If yes, then turning on the first switch will not cause the engine brake to activate....only if the position switch is in the Hi or Lo position.
As mentioned above, when you turn on the engine brake and have the position switch in either Hi or Lo, the transmission gear indicator should go from 6th to 2nd and will cause the transmission to down shift at certain rpms until it gets to 2nd gear. Once in 2nd gear and the coach continues to slow, at a certain rpm, the engine brake will disengage and allow the coach to coast.
Not sure if this answers your question or not, but it should help you understand the function and operation of the engine brake.
Ron
It sounds like you have a separate on/off switch and then a secondary switch to determine which position. Does the position switch have a "neutral" position??? If yes, then turning on the first switch will not cause the engine brake to activate....only if the position switch is in the Hi or Lo position.
As mentioned above, when you turn on the engine brake and have the position switch in either Hi or Lo, the transmission gear indicator should go from 6th to 2nd and will cause the transmission to down shift at certain rpms until it gets to 2nd gear. Once in 2nd gear and the coach continues to slow, at a certain rpm, the engine brake will disengage and allow the coach to coast.
Not sure if this answers your question or not, but it should help you understand the function and operation of the engine brake.
Ron
