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Thread: Pump Shift

  1. #1
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    Default Pump Shift

    We were out on call the other night and the pump operator had already put the pump in gear and for some reason another of our guys tried to shift the pump back to road. Of course some severe grinding occured and the truck died. I know a bit about pumps and my thought was that the truck should be taken out of service right away to drain the transfer case and check for metal shavings. Especially because I was told that this has happened a few times before. It woul dhelp alot if i could find some more info to help convince my chief to take this unit out of service until the problem is fixed? Any and all help is appreciated!


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    I did this to a truck because of my ignorance, I had the truck idling in pump and I switched off the ignition. Well this particular gem has the electrically operated air valve that supplies air to the pump shifter wired through the ignition so when it lost igniton power the air instantly slammed the actuator and gears back into road and it jumped forward a few inches with an awful crucnch. No ill effects, it was a modern 1250 Waterous for what it's worth. I have seen gear boxes take a lot worse than that and survive

    Birken

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    I would imagine this happens more often than you think. If it has been a while since the transmission fluid has been changed it would not be a bad idea to change it. The teeth on sprockets, gears, collars or shafts are hardened due to the fact that grinding does happen. I would not think that you would have an appreciable amount of metallic debris from one or two grinding occurrences. Not knowing what kind of pump you have there probably is a magnetic plug that should pick up debris if it did occur. Contact your pump manufacturer if you would like to discuss further.

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    Talking grind

    I agree with Birken that there is probably no real harm done. I can't begin to tell you how many times our guys have ground the gears and even i have done it through hurrying and not thinking. Our Waterous pump transmissons have taken some lickings and kept on ticking. Unless it is so bad it don't work right then don't fix it.

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    Recently,I was told to take the pump out of gear and my dumb axe,I forgot to shift the truck transmission(Pierce Enforcer)into Neutral before moving the PTO lever.
    With a mighty "THUNK!",the engine assumed room temperature.
    When we got back to the house,my Captain asked if I had learned anything and when I admitted my mistake,I noticed that the engineer,who had been unavailable on that call,was standing beside me and everyone else was walking away.
    "Sure,guys,why don't y'all leave me here with Mike?"
    You might guess that he doesn't like his baby abused.

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    To further address the question, on a Waterous the "gears" that are being shifted are actually what is called a "sliding dog clutch" so there are no real gear teeth to break off, rather there are about 10-15 splines going into what is a splined socket so unless all of them broke at once, the only damage that will likely happen is that they might lose some slivers off their leading edges which will be quickly grabbed by the magnet.

    I think Hale actually slides the gear itself which might be more prone to losing a tooth? But I can't exactly remember.

    Birken

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    In my FD, we call the act of taking the pump out of gear before putting thr tranny in neutral as "pulling a Wally", named after a firefighter who had a habit of doing it at least a few times a year.

    I have done it a few times myself... embarrassing as all hell, isn't it?

    You have to remember that they try to make these things "firefighter proof"...
    ‎"The education of a firefighter and the continued education of a firefighter is what makes "real" firefighters. Continuous skill development is the core of progressive firefighting. We learn by doing and doing it again and again, both on the training ground and the fireground."
    Lt. Ray McCormack, FDNY

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    Birken,

    You are pretty close on your description. It is actually called a shift collar that moves back and forth engaging either the drive shaft/coupling shaft set of teeth (road mode) or the drive shaft/drive sprocket set of teeth (pump mode). The shift collar has 23 teeth about 1.5" long. The end of the teeth is pointed to try to correct a butt tooth situation. Usually common grinding will cause the end of the teeth to become rounded. If they do become burred enough that they cause shifting problems they can be cleaned up with a file. Engagement at a high speed can cause more fracturing of the teeth and I have seen the collar with a partial split forever stuck on the coupling shaft. Most of the time it is just some rounding of the leading edge of the teeth. It does help such as in Jake's case the transmission is in high range lock-up so that when the splines do catch it kills the engine. I usually tell operators when coming out of pump to watch the speedometer drop to zero wait and then shift the pump from pump mode to road mode, then hit drive. Not allowing the pump to slow down is when most of the grinding happens. We have heard stories of shifting into pump while the engine is still moving and of the situation such as Jake's shifting while the transmission is still in drive.

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    Firstly, I'd like to know why this other guy was messing with the truck in the first place. In my department, the ONLY guy who touches any of the controls except the bleeders/drains and the siren is the driver operator. Secondly, when taking the truck out of pump..look at the nice little status lights that are right at the pump shift. I have yet to see a truck that does not have them. I don't even see how this should be an issue, except for people that have NEVER shifted a truck from pump to road, or vice versa. And even if you have never done it..almost every truck/pump builder has instructions posted somewhere near the shift, or the panel on how to transfer. I can see the rush in getting it INTO pump, but coming out of there shouldn't be a rush at all. Take your time..this shouldn't be an issue at all.

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    As advanced as new rigs are (self diagnostics, transmissions that check their own fluid level, anti-roll over technology) you'd think they'd simply install an interlock to prevent shifting when the trans is in D4. But...parts don't get sold for stuff that lasts forever. And parts make money.

    Most dealers with a service department can and will install an interlock for you when you get a new truck or to retrofit existing.

    Or a thump to the side of the head with a playpipe will learn them! (Just kiddin or course...but the thought has crossed my mind when I've seen this happen)
    Last edited by 2Chief; 08-05-2005 at 12:36 PM.

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    WELL LETS EE IF I CAN POST THE THREAD ON THE RIGHT TOPIC THIS TIME. WE CHANGE OUR TRANSFER CASE FLUID (ATF) EVERY SIX MONTHS. THIS WHAT WATEROUS RECOMENDS IN THEIR PUMPS MAINTENENCE MANUALS AND CLASSES. IT TAKES 11 QUARTS OF FLUID AND A LITTLE TIME TO DRAIN THE CASE. THE DRAIN PLUG IS MAGNETIC SO ANY CHUNKS OR FILINGS THAT COME NEAR IT ARE DRAWN IN AND HELD. THESE ARE AMAZINGLY TOUGH COMPONENTS AND I HAVE SEEN THIS DONE DURING PROBIE TRAINING MANY TIMES.(THATS WHY WE TRAIN WITH RESERVE EQUIPMENT) I PERSONALLY HAVE NEVER SEEN THIS MISTAKE RESULT IN TRANSFER CASE DAMAGE.
    Last edited by streetwise; 08-08-2005 at 12:32 PM. Reason: WRONG POST

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    ONE MORE THOUGHT ON THE TRANSFER CASE. THE FLUID AND FILTER CHANGE INFORMATION CAN BE FOUND IN THE WATEROUS MANUAL. THE FOLKS AT WATEROUS HAVE ALWAYS BEEN SUPER TO MY DEPT.AND ME. I HAVE CALLED THESE FOLKS FOR A MULTITUDE OF REASONS AND THEY HAVE NEVER FAILED TO HELP. Stay Safe
    Last edited by streetwise; 08-08-2005 at 12:39 PM. Reason: WRONG POST

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    WOAH!!!! easy on the caps streetwise. As I said..there should not be a reason that this shou;dl even happen. I just don't understand what it so damn hard about taking five seconds to make sure everything is ready, and where it needs to be before shifting it out of pump.
    FF/NREMT-B

    FTM-PTB!!

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