Does anyone have any knowledge about Allison, PTO, or yard mule hydraulics. I've bought a fire truck, a 1990 GMC Top Kick 7000 It grosses at 28000 so I'll remove the fire body, and pump, add a flat bed dump body with sideboards. It won't carry tandem weight. I'd estimate body, and load together at 17000. My engine is a Cat 3208Turbo. Try as I might I can't find room for an engine mounted pump. Shaft drive off the front of the engine isn't going to work as the radiator is in the way, and includes coolers for transmission, and engine oil. I'm down to PTO as best choice. I find PTO with married hydraulic pumps of unknown specification. I'm needing at least 5GPM, 2500 LBS. Am I going down a wrong road?
Shouldn't be hard at all to find a PTO for an Allison. I will bolt on the same as they do on any standard transmission. We used to have a IH with a DT and MT653. You put the transmission into gear to engage PTO, then back to neutral and away you go.
Willy ... find a nearby PTO specialist company and tell them what you want to do and what you have. It wont be cheap, but it will be right the first time. I have done a bunch of Pto/Pump installs and that's the best way to go.
It appears NH is the nearest. Their lack of knowledge was disheartening. I was told I couldn't move the truck with PTO engaged. I am now convinced that is not the case. While having it right is important, I wasn't left with confidence that 8 times the cost would improve the likelihood of a successful outcome. Allison has You Tube videos about PTO on their transmissions. I presume they are talking about current production transmissions. They talk of the drive gear mounted to the secondary half of the torque converter. It is necessary to put transmission in drive, but stationary, (foot on the brake) to engage. Then if you want stationary, place in neutral. This trans. is old, but I believe it holds true. Because these PTOs are powered through the torque converter, they won't work well at high power PTO load with the engine at idle. Willie
I don't believe any PTO will stand up to very much load. The one we had would raise 14 yds of dirt right up with the truck idling, no problems.
You might contact Muncie or Chelsea directly with what you got you get you the rite model so you can then order the proper one from the local dealer
You seem to be collecting a huge pile of misconceptions here. First... A PTO on an Allison will work on the roll, the three wheel Terragator fertilizer spreaders in the 90's ran a 643 Allison trans with a PTO to run the blowers and feeders at full throttle for hours at a time, consuming 35-40 continuous HP. Second... How do you run a dump with a stick trans? Engage PTO, raise box, push clutch in, put in gear, and drive. Allison isn't much different. Been around this stuff 45+ years, it's very doable. I think you're listening ton the wrong people.
We've got 3 Ford dumps at the farm with Allison MT653 trans and trans PTO. they work just fine like Shimmy says. They'll hoist a full box at low to medium idle. You do have to engage PTO while trans is in gear. We use reverse since that's always our last motion before dumping. Engage PTO, shift to neutral, then hoist. Otherwise you are power braking the trans to stay in place while hoisting. They will operate while idling forward , but screech and squeal bad if you go to take off without disengaging PTO. Only time we ever use PTO while pulling forward is when using power down function to reduce cycle time.
My old truck came with dump body manual. It cautions against more than 1800 RPM with PTO engaged. Yes I do tailgate spread with PTO in gear. I hope to be able to do the same with the Allison. I see wood splitters with 5 HP engines providing plenty of hydraulic for my needs. Therefore I don't feel it'll be any strain on a PTO rated at ?100? HP. I do understand the torque converter may not turn without a bit of throttle, in the same sense it won't move the truck at idle. The used unit is on its way. I made that decision last week. Compared to new, it was cheap. I'm well conscious I'm taking a big risk here. I've found no info on the needs of yard mules, but I'm banking on it being at least 5GPM. If the dump action is slow, I'll live with that. This isn't a production truck. It's an old man hauling wood, logs, debris, sand for bedding conduit, driveway gravel, and drainage stone. Now and again, towing a heavy machine on a trailer, or carrying a bulldozer as in my avatar. Willie
what model pto did you use on the Allison trans? I'm doing the same on an old fire truck.
I'm pretty sure you can go to Chelsea web site and find your transmission and find your PTO model.
Aren't the fire pumps powered by a PTO? I have a former plow truck with pump off the crankshaft. It lifts at a constant speed no matter what RPM. It's not as nice spreading material as a PTO pump specific for dump boxes like I had on single axle dump. Pumps for dump boxes are designed to bypass when fully lifted so you don't run against relief pressure. You can let the box dump as you drive and don't have to worry if goes to full height. It won't hurt anything. The new dump truck you have to keep a switch pressed all the time and stop when it reaches the end of travel.
Willy, is that the truck that was parked down by Emerald Lake ? I was hoping that old girl would find a new life.
It has been years, I'll update. After three used PTO units each arrived damaged beyond function, I went in search of someone who did know. If I recall, the married PTO & pump were in the $1500. range. There was some question that some Allison transmissions were built without the needed gear to drive a PTO. Luckily mine did have it. Works flawlessly as I hoped it would. This was E One fire truck. A short driveshaft from the transmission powers the water pump, There is a gearbox built into the pump assembly. Another short driveshaft from pump to rear differential. To pump water the pump gearbox disengages the rear wheels. To drive, it disengages the pump. Removed the pump, had a driveshaft built.
No, That is a Chevy, older than my GMC. It hasn't moved in a decade. It was shiny when parked there, it looks pretty dull now, Says Sharon on the door.
The finished build is prone to not hoisting at idle, torque converter doesn't turn until a bit of throttle. Dumping heavy loads requires 1000 RPM.
Yeah converter driven pto's are something else, I've ran engine driven ones l my life and my equipment is converter driven. In the winter I have to pur it in gear to spin the draw works then turn on the pto then wait a good 10 minutes until it starts spinning the transmission output like it would in summer. It doesn't help I have 15w40 in the transmission