Hydrostatic transmission problems

[jdance49]

Was mowing in high weeds today and tractor seemed to just pop out of gear. It is a hydrostatic transmission....everything else seems fine but it won't go anywhere.....anybody got any suggestions also noticed that rear pto is not engaging

 

[Hooked_on_HP]

It is a hard question to answer when you dont tell what tractor you have.
Bill

 

[texasjohn]

Wild guess.... check linkages between HST pedal to transmission ...... is it flopping loose, leaving it in the center, no motion, position?

 

[jdance49]

It is a hard question to answer when you dont tell what tractor you have.
Bill

It is a New Holland TC29D....The rear pto doesn't engage either. It like it just slipped out of gear as I as mowing....I have tried to put it in all three speeds but still nothing.....all linkages are tight underneath the hydrostatic foot pedal

 

[jdance49]

Wild guess.... check linkages between HST pedal to transmission ...... is it flopping loose, leaving it in the center, no motion, position?

Have checked them all....they are tight....It seemed like while I was mowing it just popped out of gear.....

 

[jinman]

I looked at the parts diagrams for your tractor, but there is not one overall view that shows where a common part might fail and cause your problem. I'm thinking that something simple like a splined collar between two shafts has let go or slipped out of position. I'm just not sure how the PTO driveline goes through or by the HST on your tractor. I can't get my mind around all the parts diagrams enough to figure that out. It is possible that your clutch has let go, but you would surely have heard something rather than just a sudden loss of all gears and PTO. The unfortunate thing about all this is no matter how simple the fix, you will have to split the tractor to find/fix the problem. I just don't expect this to be a simple problem that can be addressed externally.

 

[JC-jetro]

Have no experience with HST transmission. Is your PTO engaged hydraulically? can you measure or inspect HST pump pressure? do you know if you have flow to your Hyd motor?

JC,


Edit:

I went to NH site and briefly looked at the mechanism. It looks to me the Pto final shaft is directly coupled to transmission input shaft going thru the HST pump/motor assembly. In other words if the engine is on and clutch out the PTO input shaft should be turning anytime the engine is on. The coupling between pto final output shaft and the pto input shaft is done by a sliding coupler. If I'm correct then with the engine off, I'd engage the pto without any implement attached to it and then turn the engine on. when I let go of the clutch the pto should be turning even if I have HST pump/motor issue. I'm thinking you might have an issue with the main clutch not turning the hst input shaft.

Rick will be here soon to sort it out.

 

[Carykong]

when you say everything "seems fine." You did check your hydraulic level,right?

 

[Jbrink64]

Something failed between the flywheel and the HST. Either the clutch disc/splines or HST input shaft.

 

[jinman]

when you say everything "seems fine." You did check your hydraulic level,right?

Cary, on the TC29D, the PTO does not rely on hydraulics like on our tractors. It is always a good idea to check the fluid level for HST function or main hydraulic problems, but on the TC29D, the PTO is mechanical and a mechanical failure is indicated by the symptoms.