JD 4400 HST transmission chatters

[Kyle_in_Tex]

From the 4310 ehydro troubleshooting manual,

(1) Poor Transmission Performance?
Yes - Loss of charge pressure.
Yes - Low hydraulic fluid level.
Yes - Plugged filter.
Yes - Improper current to solenoid valve.
Yes - Solenoid valve malfunction.
Yes - Plugged screens at solenoid valve.
Yes - Worn rotating kit components.
Yes - Parking brake is on.
Yes - Ballasted too heavily.
Yes - Wrong valve installed.

 

[texasranger556]

Thanks Kyle.

As luck would have it I talked to my dad yesterday about my theory and explained what to look for. Tonight he called and said after taking out the charge pressure relief valve, it looked like the poppet was sort of off center when he pulled it out. Cleaned out the hole with a magnet and a rag, put it back together and now it drives like brand new! Nice and smooth even at idle. Gotta love it when a theory comes together! Too bad we didn't check that first before splitting the tractor and re-finishing the plates, but only cost us time, some sealant, and $15 for the manual. Now to get it hauled down here and start building my shop :cool2:

Cheers
Ryan

 

[Kyle_in_Tex]

I'm glad you got it fixed and that it was something simple. Now you have given an answer that might help the next guy down the road.

 

[Little General]

I was having the same problems with my 4400. It was jerking, barely lifting lift arms,squealing when operating go pedals.I hate to say this , but my tractor came from a landscaping company and at 1444 hours, the oil screen had never been serviced. It had so much crap on it > There was so much metal chunks and shavings it looked like something had broken. It seems when JD made these tractors, they didnt do a good job removing the scrap metal parts. Anyway, a new filter,gasket and $200 worth of JD hydro oil and she is purring like a kitten.

 

[texasranger556]

Sounds like classic oil starvation/pump cavitation, good work fixing it.

I'm not so sure that a significant amount of metal is left in the system from the factory, most OEMs do recommend an initial service to address that. Over time the gears, diff lock, clutches, and bearings all wear and introduce particles into the system, especially if abused. Keep up with filter, screen, oil changes/cleaning and things will last.

 

[dfkrug]

I'm not so sure that a significant amount of metal is left in the system from the factory, most OEMs do recommend an initial service to address that.

I am sure they all have significant amounts of metal particles in there, left over from manufacturing. I was initially shocked to see what I got out of my new Kioti when I drained the fluid right after I got it new.

These particles don't really cause any problems, however, as they are caught by the filters. Unless/until they overwhelm the suction screen. The JD 4200/4200/4400 has a large suction screen, but they also have a problem with the PTO brake breaking down and shedding excessive amounts of debris into the sump.