Retard switch
My neighbor just bought a new 2013 Fleetwood Expedition 40X with a 360HP Cummings and Allison transmission on a Freightliner chassis. We were talking about the "Retard" button and he said the owners m...
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Suspect it will be either an EXHAUST BRAKE or VGT (VARIABLE GEOMETRY TURBO) that gives braking HP when used, particularly since the Allison transmission will likely/certainly should be programmed to downshift when the brake is engaged. A quick call to Cummins with your engine serial number will tell you exactly what you have: Cummins 800 343-7357.
If he has the two window shift pad, the left window will indicate the "pre-select" gear. When the retarder/exhaust brake is engaged, it will change from "6" to the pre-select gear, which as Wally said is generally 2nd or 4th, but can be changed by an Allison dealer to anything you want.
If he has the two window shift pad, the left window will indicate the "pre-select" gear. When the retarder/exhaust brake is engaged, it will change from "6" to the pre-select gear, which as Wally said is generally 2nd or 4th, but can be changed by an Allison dealer to anything you want.
