John Deere 4400 hydrostat transmission

WVhillside · Sep 17, 2011

Folks,
I have John Deree 4440 hydrostatic drive and the hydro quit working,tore tractor apart not a thing wrong with any of the gears etc. This is not the ehydro,dealership said they could not test pump unless it was in the tractor and I think they may be confusing it with the ehydro,anyway the pump is out and surely they can bench test this thing some where, my question is where and who is a reliable outfit who specalizes in hydro repairs for John Deere 4400 series. Anyone here have an experience with or suggestion would be appreciated.
It had plenty of fluid in it and the fluid was as clean as the day it was put in.
Any thoughts suggestions would be appreciated.

joecdeere · Sep 17, 2011

Deere's test procedure usually is with the unit together.

ducks13 · Sep 17, 2011

I'd suggest looking for a hydraulic repair shop but I really don't know much about this. What I do know from years of diagnosising automotive problems is that you should never take it apart until you already know what is wrong. As the dealer and the other poster mentioned, thing are usually tested while they are still together. I guess the only exception to my rule would be some kind of internal mechanical noise but there should still be some diagnosis before disassembly. Just wanted to help you in the future and other who might be reading.

kennyd · Sep 17, 2011

I think you made a HUGE mistake by taking it apart with troubleshooting. There are very simple and specific test outlines very clearly in the FSM (factory service manual). This could have just a $50 part to fix before...

WVhillside · Sep 17, 2011

WVhillside said:
Folks,
I have John Deree 4440 hydrostatic drive and the hydro quit working,tore tractor apart not a thing wrong with any of the gears etc. This is not the ehydro,dealership said they could not test pump unless it was in the tractor and I think they may be confusing it with the ehydro,anyway the pump is out and surely they can bench test this thing some where, my question is where and who is a reliable outfit who specalizes in hydro repairs for John Deere 4400 series. Anyone here have an experience with or suggestion would be appreciated.
It had plenty of fluid in it and the fluid was as clean as the day it was put in.
Any thoughts suggestions would be appreciated.

We never touched the hydro transmition we just pulled it out of the tunnel,we tore into the gears to verify they were alright,we have had the tractor apart before,the only thing we done was pull the hydro out of the tunnel and never touched the hydro internally.

beenthere · Sep 17, 2011

Maybe time to just put it back together and run through the troubleshooting procedures. Would be a pretty expensive test stand to make the pump operate outside the tractor.

By the way, :welcome: to the forum.

atschirner · Sep 17, 2011

While you have it apart check the suction screen behind the inlet line to the pump. I thought my 4400 was toast until I pulled that part out and found it covered with gray slime. I washed it out, changed the spin on filter and filled it back up with JD's finest hydro fluid. Works like new now.

This all happened to me the first week I owned the tractor with 960 hours on the clock.

WVhillside · Sep 17, 2011

beenthere said:
Maybe time to just put it back together and run through the troubleshooting procedures. Would be a pretty expensive test stand to make the pump operate outside the tractor.

By the way, :welcome: to the forum.

You maybe right I should put it back together...I with the help of my cousing we have had this thing split before and done numerous other things to it but the hydro is a whole different thing then just working on the gears etc.. love the hydro when it is working ,but who dosen't like something when it is working right.