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

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Permalink Reply by Shawn Tibbitts on March 3, 2009 at 11:17pm

I have never heard of doing that, however I have had the luxury of only driving automatics. The way I see it as long as the truck is shifted into neutral before the pump is disengaged I don't see how it could hurt putting it into forward or reverse. I take that back I would have to imagine that their would be less wear and tear by going into drive when your ready to leave reason being and this is only a thought and not by any means proven fact. I would think that it would be easier on the mechanics to continue the revolution of things in the the direction of which they were running however that being said once the pump is disengaged nothing is running to it anyways so no it shouldn't make any difference. I think I confused my self on that one:) Hopefully you got the gist of what I was trying to say. After thought....... we just had the pierce guy down a few months ago, going over our quint and he never mentioned anything like that to us and he was pretty thorough going over all the ins and outs. Im not an expert but I wouldn't worry about it either way. Worst case scenario just give pierce a call and ask, their going to be your best source of advice.

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Permalink Reply by Chris Steeves on March 4, 2009 at 7:09am

I have never heard of going to reverse to sync the the rig after returning the pump to road. I have however only driven automatic rigs. I have ben through pump classes put on by Hale and Waterous as well as classes presented by manufactures ( KME, E One and Saulsberry) and never heard of this. Hope this helps with the possible firehouse myth.
Good luck
Make it safe
Chris

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Permalink Reply by Vincent Gatti on March 4, 2009 at 10:35am

Can't beat the mgf's recommendations. That being said, I started out with manual trannys. We were always taught to place the trans in neutral and wait for the speedo to stop on "0". From there, it was a matter of disengaging the pump shift. No difference with automatics. Nothing was ever said about placing trans in reverse.

Stay safe

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Permalink Reply by Jared Larna on March 4, 2009 at 3:17pm

I don't know if this will help you or not with the "myth". One of the hats I wear is heavy equipment mechanic. Nuts and bolts of a P.T.O.( power take off that drives the pump) P.T.O. is mounted to the side of the transmission with a protruding gear. When you engage the pump an actuator slides the P.T.O. gear and meshes with a gear in the trans. It also disables the drive gear to the engine. When you put the engine back in gear, the transmission tranfers power from the motor directly to the pump. Of course this is a simple set up and there are others out there but the concept remains the same. Back to forward or reverse after disconnecting the P.T.O. Unless the manufacturer of the TRANSMISSION states that a certain step be taken to "remesh" the trans. I see no need to do either. Use of the P.T.O in no way other than disableing the drive gear alters the drivability of the engine. As long as the engine is placed in neutral and enough time is allowed for the trans gears to come to a complete stop when engaging/disengaging the pump there should not be any damage or change to the "Meshing" of the trans.
FYI Hope this helps

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Permalink Reply by Vincent Gatti on March 4, 2009 at 5:58pm

PTO is a much different animal than a transfer case. PTO takes power from the transmission whereas the transfer case takes power after the transmission (power transferred from drive line to pump rather than to rear differential). PTO connection allows vehicle to "pump and roll" while a pump with the transfer case must be stationary. I'm NO EXPERT just relating what I've seen in the fire service.

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Permalink Reply by Jared Larna on March 5, 2009 at 8:18am

This is true as well. Same type of actuator different set-up. I still don't see a need for going into reverse before driving. The important thing is that the trans is in neutral and completely stopped before engaging/disengaging pump gear.

Vincent Gatti said:

PTO is a much different animal than a transfer case. PTO takes power from the transmission whereas the transfer case takes power after the transmission (power transferred from drive line to pump rather than to rear differential). PTO connection allows vehicle to "pump and roll" while a pump with the transfer case must be stationary. I'm NO EXPERT just relating what I've seen in the fire service.

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Permalink Reply by Ed Laugesen on March 12, 2009 at 2:44pm

I have never heard of anything like this, I got my start on a 1952 Peter-Pirsh on a Ford chasis. It had a non-syncro standard tranny and we just made sure the speedometer was on zero and the pump stopped before shifting back into road gear. We still teach that in my Department, even with the new automatic units. I do know from having to have a Waterous transfer case rebuilt that you have to wait untill everthing is stopped before shifting or you will grind the points on the gear teeth which help align the gears flat on the slide ring, then it won't shift properly.

Good hunting

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Permalink Reply by Bob Franklin on March 20, 2009 at 12:44am

Hey John
When taking the pump out of pump position to road position, when you go to nuetral, watch the speedometer. It should read 0 and may bounce at least once, then flip the control switch to road position. The reason for going into reverse is to reverse the torque and line the shaft splines up otherwise it will grind when attempting tp shift. Also make sure the engine RPMs are between 5000 and 7000 before attempting to shift.

If you get a achance come see me at FDIC "Let's Talk Pumps" and i would be glad to discuss it with you.
BOB

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Permalink Reply by Trey Fludd on March 20, 2009 at 3:24pm

You would be better off finding that information out from the manufacturer of the transmission. I have never hear that here

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Permalink Reply by Vincent Gatti on March 20, 2009 at 3:58pm

"Also make sure the engine RPMs are between 5000 and 7000 before attempting to shift."

Too many zero's. I'm sure he meant 500 to 700 RPM's

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Permalink Reply by John Robinson on March 21, 2009 at 4:51pm

Jon

I am the maintenance officer/mechanic at my department. I have two of the same trucks ( 96'and 97' model with DD 6V92 ) and have rebuilt both of the pump transmissions. I have stuggled for years with engineers over the proper operation of the road to pump transfer. I have a power point which includes pictures of internal parts and explains in detail how the transfer case works. Educating engineer first is very powerful when sharing the correct way to shift in an out of pump. Most think its just flipping the switch. I will send you this information if you would like it. Pierce will refer you to the operation manual for the Waterous Pump. I found a gentleman at Supple Brothers in PA. He has worked with Waterous for over 40 years. I beleive he is the authority on all things Waterous and I am very greatful to him for his advice.

Using reverse is not necessary in a properly operating rig. However it is in my SOP for going into Pump and Back to Road. The use of reverse seriously reduces the potental for damage by allowing the transfer collar to properly align using the non-moving gear in the pump transfer case. I have expiranced the damage first hand.

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Permalink Reply by Russ Chapman on March 25, 2009 at 11:09am

Bro
That is called "Buck Toothing". That is to be used only if the rig did not go into pump gear to begin with.

The best way to take a rig out of pump is to follow the manufacturers recomendatioin. Anyone who starts to deviate from that will null and void any manufacturers responsibility in the event of a malfuction. The first step is to place the transmissoin in neutral.
If you have a pnuematic 3 position pump shift, move the lever to the center or nuetral position. Then my advice is to go and find something to do for a couple of minutes. Come back and place the pump shift into Road. This gives the gearing time to "spool down" and allow the pump transmissoin to slow down. If it is a 2 position pump shift, place the drive transmission in neutral, then wait for about one minute then shift to road.
If you have a electric pump switch, use the speedometer to come to 0 and then shift back to road.
No matter what type you have, be patient and allow the pump transmission to spool down.
Russ Chapman
Aerial and Pump Certification instructor
Conn. Fire Academy

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