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What is the "Best" way to remove the engine from pump gear??

There is some debate at my house as to the best way to take the rig out of pump gear. Some of the guys have heard that after the rig is in neutral and shifted from pump back to road that it is best to shift the transmission into reverse so that the rig can "synchronize". One of the guys said that he was told at a pump class by the pump manufacturer, one guy said he was told by our mechanic, another said the apparatus manufacturer recommends it. Sounds reasonable, but I have my doubts only because I was told to do the same thing many years ago when coming out of pump gear, but that was on a manual transmission and the "old timer" that told me to do it said, "Listen for the back up alarm and you will know you are out of pump gear, kid." At the time that sounded reasonable until I heard that one of our guys had tried to pump a fire in reverse. So, I have check F.E. forums and gone to the pump manufacture's website with no luck finding any info. My rig is a 97 Pierce Saber with a Waterous Pump (CM 1250 gpm). I don't mind putting the rig in reverse I just don't want to do it for the next 10 years and find out it was a Firehouse Myth.

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Permalink Reply by Bob Franklin on March 30, 2009 at 2:12am

Hi John,
As a Waterous Field Mechanic for over 35 years, here is what you have. The allison automatic transmission has torque that nevers lets the driveline stop turning when you shift to pump gear. Even though the transmission selector swith will be in the nuetral position, the drive live continues to turn. Some times this will not allow th splines on the shift collar gear line uo with the pump drive gear.(Butt-Toothing). In ordger to line up these splines, shift transmission to reverse, then neutral and then into "drive" position. This shifting to reverse allows the gears to line-up and complete the shift. Now lets take it out of pump mode and back to road position.
The speedmeter should indicate about 10 to 18 mph while in the neutral position, watch the speedometer dial, sometimes the will bounce twice when you place it into neutral after pumping, after the "second bounce" shift back to Road position. As the apparatus ages, depending on the amount of incidents it responds to, the transmission, not the transfer case, may require you place the shifter into reverse and back to drive to get the splines to line up.
If you get a chance to got to FDIC, come see me at LET'S TALK PUMPS, Thursday April 23 in room 206/207. I will be discussing this very problem.

Take care & hope this helps,
Bob Franklin

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