John Deere 4440 PTO clutch and gear problem

[crissangel]

I've got a John Deere 4440 with an 8speed power shift, mostly used on a TMR mixer. It ran great at first , but eventually started bogging down and stalling in 1st and 2nd gear, both forward and reverse. We opened the transmission and found the PTO clutch pack was seized, so i replaced the clutch plates, drum, packings, gaskets and a couple of internal plates. After putting it all back together, the same issue is still there. I cleaned the speed selector valve and even swapped in a used one, but nothing changed. A mechanic thinks its the valve, but i'm not convinced. Any thoguhts?

 

[Brad Pith]

Sounds like you've done all the right steps so far, I'd look next at the hydraulic pressure, maybe the pump or relief valves aren't holding pressure properly or could also be internal wear causing slipping under load, be checking the specs while running

 

[pasture2barn]

Since rebuilding the clutch didn't fix things, let's look at your transmission's main relief valve and pump pressure. A stuck PTO clutch can gunk up the hydraulic system, blocking flow to the shift areas. Also, check the charge pump. If it's weak, shifts might feel soft, especially in lower gears that need more pressure. Don't forget the hydraulic filter, it could be clogged from the old clutch breaking down.

 

[Corrupted_Stone]

Did you test hydraulic pressures under load? If the PTO clutch isn’t getting full pressure, it’ll stall under load even with new parts. Also, inspect the PTO control valve (sticking or mis-gapped valves), that can block or bleed pressure.

 

[0ldfashioned]

I've got a John Deere 4440 with an 8speed power shift, mostly used on a TMR mixer. It ran great at first , but eventually started bogging down and stalling in 1st and 2nd gear, both forward and reverse. We opened the transmission and found the PTO clutch pack was seized, so i replaced the clutch plates, drum, packings, gaskets and a couple of internal plates. After putting it all back together, the same issue is still there. I cleaned the speed selector valve and even swapped in a used one, but nothing changed. A mechanic thinks its the valve, but i'm not convinced. Any thoguhts?

Your mechanic might be right about the valve, but not the selector valve. Since it bogs in both FWD and REV in the low gears, check the Main Pressure Regulating Valve or the Priority Valve.
If the pressure is weak, the low pressure clutches won't engage cleanly