Silage trailer pto

A few things I’ve run into over the years with sawmills that may be helpful…
Old lines shed crud into the lines and plug fittings up. Check your filters for crap. if it’s in the filters, it’s in the lines.
had a piece of hose clog my relief valve that did something similar to what you’re experiencing.
Under load, its sucked. Free rolling it was fine.
Air in the fluid can cause issues too. See if your return line to the tank is foamy. Bleed the system to remove air.
Water in the system. This is a nightmare of its own. Only solution i ever came up with that worked was replace the fluid.
I’m betting you have a blocked valve or fitting that’s causing pressure back up that stalls the motor. That’s what it sounds like to me. Something is blocked or plugged or backwards. Process of elimination to locate it. Need a bypass hose to bridge around fittings and such. Start at the high pressure coming off the main pump and work down the line until you find it.

 

Do you have a pressure gage on the trailer?

IF you do not, get one, use it first the the connection between the truck and the trailer, then at the motor.

 

Are you absolutely sur your replacememt motor was the same as the original? Hydraulics cam look EXACLY the same on the outside, yet bw completely different inside. It almost sounds like your new motor is set up for higher RPM but lower torque. Have seen this mistake before with my own eyes.

 

Not familiar with this trailer or setup, but have worked on hydraulic systems before.
Once you open the system and replace components, is there a bleed plug somewhere (preferably higher in the system) to get rid of any air that may have got into the lines? Or is it self-bleeding?