Operating PTO in auto tranny

Just bought our first dump truck that is not a manual. All of our grain trucks are manuals and you can operate the PTO dump hoist with the transmission gear engaged. As in you can spread the rock without having to stop to engage PTO. This new truck which has an Allison automatic transmission, the pto will only engage or remain on when the gear select is in neutral. Makes it hard to spread a load of rock when going back and forth to drive and stop to raise a bit more. Is this how these new trucks are supposed to work or is there a way around that “safety” mechanism? It was an old city truck so not sure if it was an osha requirement or what.

You didn't bother mentioning any description except Allison. My Allisons in dump trucks can operate PTO in any range, but, when in gear, the truck must be moving.
My Allison in my street sweeper must have the maxis applied to operate the PTO.

My avatar has a Allison and PTO, the trans in gear shuts the pto down until moving. Either don't spread rock with it or be in gear moving when trip the gate, no other way to do it. Pretty much the same as manual trans when spreading.

heymccall said:

You didn't bother mentioning any description except Allison. My Allisons in dump trucks can operate PTO in any range, but, when in gear, the truck must be moving.
My Allison in my street sweeper must have the maxis applied to operate the PTO.

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What kind of sweeper do you have ?
We have a fleet of Elgins but the truck type all use an auxiliary engine.

DB2 said:

What kind of sweeper do you have ?
We have a fleet of Elgins but the truck type all use an auxiliary engine.

Click to expand...

Ford CF7000, 5.9 Cummins, Allison 4 SPD, Perkins sweeper engine in a Johnston 605...PTO is solely for bed hoist and rear door.

Sounds like a hotshot pto and has the engagement circuitry routed through the neutral safety switch. I used to wire fuel trucks and lube rigs the same way, saved a lot of pumps and compressors from being trashed if the driver forgot to disengage the PTO. Yes I also put lights and buzzers on them... but things happen.

We have auto that was set up like that had be be in neutral to run pto well at least until that got "fixed" its a safety lock out to keep you from going down the highway with the pump on

My '05 C5500 and '07 C7500 both cap the RPMs when in gear, and in neutral, with PTO engaged.