JD 955 NO PTO, NO FLUID pressure

[Hoopcoachd]

Hit a small stump with bush hog just after engaging. Lost PTO output and all hydo..no trans, no pump. Does input shaft have a shear pin or key? What now?

 

[Kevin M]

Welcome to TBN , We are going to need some more info, I'm assuming the engine is still running ? If you shift the PTO selector to your Mid PTO does that work ? Have you tried changing ranges, (high to low) on the Transmission ?

 

[psdx]

If there's no weird noises when you engage the PTO or the transmission and there's no leaks it's probably not terrible news. Wish I could answer your question directly. Good luck.

 

[Hoopcoachd]

No noise when PTO is engaged - nothing. Engine runs great but NO hydraulic pressure to transmission, front loader, or 3 Pt Hitch - nothing. No leaks, changed the filter and fluid; fluid was clear - amber, like new. My question is: Is there a shear pin or key b/w the drive input and the PTO shaft b/c the PTO shaft drives the hydro pump. I'm good with cars but this is my 1st tractor. '98 JD 955 diesel, less than 800 hours...

 

[beenthere]

Hoop
Am thinking you need to do some pressure checks to see whay the hyd. system is down. With this attached info on the PTO operation it looks to be dependent upon hyd. pressure in the system to engage clutch and brake. So am thinking it may be as you suspect, and the pump coupler (line 11, second attachment). Removal shown in 3rd attach.
See attachments for tech manual comments found that might help.

 

[Hoopcoachd]

How about a pin that connects the engine shaft to the hydraulic pump - it isn't splines, has sort of a u-joint held together by a pin. I will have time sunday to pull the floorboard and check - makes sense that when both PTO and hydraulics go at the same time it has to be a drive-link of somekind.

 

[beenthere]

After the 'floorboard' is removed, should see the drive shaft from the engine back to the charge pump has a double bolt connection shown in the first plate.
The second plate shows the charge pump cover removed. There is mention of a pin (A) that may become worn and is to be changed out if worn (charge pump cover off). Not very good renderings from the tech manual but that pin may be the culprit.

Good luck with what you find.

 

[Mechanos]

The driveshaft from the flywheel back to the transmission connects to a shaft that runs straight through the transmission. That shaft connects to a shaft that runs through the transaxle and drives the implement pump. The fact that you lost power to both the trans and the implement pump at the same time, would suggest that power isn't being transmitted to the input shaft on the trans.

 

[Mechanos]

Took a look through the repair manual at how the trans input shaft engages the trans charge pump and how the trans input shaft connects to the transaxle mainshaft and how the mainshaft connects to the implement pump. I hate to say it, but I suspect you've snapped the trans shaft in two.

 

[Hoopcoachd]

Thanks so much for your thoughts...I will get it apart after church on Sunday and let you know. Several people say that the pin is likely bad, says it happens with regularity. Hope its notthe shaft but...have to wait and see. Thanks again.