Allison MT 653 pto issue on 94 F700 dump
Last fall I had intermittent issues getting dump box to lift. My mechanic traced it back to pto gear not turning the pump. My question is how is the pto gear set up? Zero metal shavings or debris was in the fluid or magnet in the pan and the intermittent operation before it quit completely has me baffled. It seemed to work after fluid got heated up before it quit entirely but that may be circumstantial. I hate to give up on the truck if it's an inexpensive fix. It was a municipal truck and only has 35,000 miles on it but probably a lot of dump cycles for background info on the truck. Drives and shifts perfectly but zero fluid being pushed through hydraulic pump when pto is engaged. |
Need to know the make of the PTO is it cable or air operated. Pretty simple a sliding gear slides & meshes with the trans counter shaft. If the PTO drive shaft is turning then its a pump problem. I'm not understanding the
"seems to work after fluid gets heated up" The system does not work hard enough to get heated. |
Originally Posted by big job
(Post 18116782)
Need to know the make of the PTO is it cable or air operated. Pretty simple a sliding gear slides & meshes with the trans counter shaft. If the PTO drive shaft is turning then its a pump problem. I'm not understanding the
"seems to work after fluid gets heated up" The system does not work hard enough to get heated. |
Is the pump mounted directly to the pto or does it have a drive shaft connecting them?
Not knowing the brand and model of your pto it hard to say if it's clutch operated or direct direct gear engagement. There's a gear in the trans that drives a gear in the pto, if you where having issues with these you would have heard a bunch of grinding and gear noise, you would also have metal in the trans fluid. Any issue your having will most likely be in the pto or pump, not from the transmission. You probably have ether bad clutches in the pto if it has them, stripped splines where the pump mates to the pto, or a sheared key in the pto shaft. Get under there and look to see what you have and get the numbers off the tag on the pto. |
Originally Posted by Destroked 450
(Post 18117337)
Is the pump mounted directly to the pto or does it have a drive shaft connecting them?
Not knowing the brand and model of your pto it hard to say if it's clutch operated or direct direct gear engagement. There's a gear in the trans that drives a gear in the pto, if you where having issues with these you would have heard a bunch of grinding and gear noise, you would also have metal in the trans fluid. Any issue your having will most likely be in the pto or pump, not from the transmission. You probably have ether bad clutches in the pto if it has them, stripped splines where the pump mates to the pto, or a sheared key in the pto shaft. Get under there and look to see what you have and get the numbers off the tag on the pto. |
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