any John Deere mechanics ?

[flyinlow]

My GX 325 gardentractor is having transmission problems.  Hydrostatic drive has become very noisy. Fluid gets hot after 30 minutes and expands ,overflowing the reservoir. Deck lift wont work.
Changed fluid and filters, linkages are free, drive belt ok and tight.  450 hours on the machine.

[Tilar]

Sounds to me like your hydraulic fluid is going over relief. That would cause the noise and the fluid getting hot fast and overflowing.

I'm not familiar with the hydraulic system on a lawn mower, but it has to have a relief either in the filter which you have already changed, Or elsewhere in the system.

Do you by chance have an auxillary hydralic valve that might have been bumped on or is not going all the way to neutral? This would also cause this same thing.

[flyinlow]

There is a drive disconnect lever { bypass) that is pulled to push the mower manually . It does not feel like it use to. and the drive does not free up like it use to. The only other external connection beside the foward/backward control is the deck lift actuator. I capped the lines to it and it made no difference. You can feel the hydraulics "kick" back thru thr forward pedal when the fluid gets hot and the mower slows to crawl.

[elacruze]

Is it noisier hot than cold? Have you cut open the filter to inspect for metal?

Your fluid cooler could be plugged or airlocked if you have had the fluid out.
Noise can be caused by aerated fluid, which will also make the response mushy.

If you don't find any metal in the system, change the fluid (Deere's recommended fluid is pretty good) and filter, bleed the system by the book and be sure you don't have any pinched or kinked lines, particularly the main feed line from the reservoir to the pump.

Pilot pumps (hydrostatic drive) use pressure feedback internally to control the pump displacement and air in the system can cause them to feel mushy, fail to change volume, and will eventually lead to pump or driven motor failure.

[flyinlow]

Thanks for the info, the internal filter looked ok and the other that protects the deck lift valve and actuator could be blown thru. Only a small amount of fine  metal particles in the hydrualic fluid. JD dealer  said that was ok. I suspected a messed up valve.They are all internal in the trans. ( Tuff Tork 71A) Will probable have to tear it apart now that the season is over, or take it to the dealership 

Does get noisier as the trans heats up and gets slugish. Cooler is a fan that runs with the engine and blows air over the fins on the trans. The trans has a remote resivoir and should self bleed. Never had to add fluid between changes before and the fluid was bleed within a few minutes of running after previous fluid/filter changes.

[Todd Wilson]

Will probable have to tear it apart now that the season is over, or take it to the dealership 

You'll get the big green weeny stuffed in from behind if you take it to a dealership. Hope you get it fixed. Dont know anything about hydrostat stuff.


Todd

[elacruze]

. Only a small amount of fine  metal particles in the hydrualic fluid. JD dealer  said that was ok.

Bad JuJu.

How old is it?

[ACUDANUT]

 A john Deere Mechanic and a Lawn Mower (garden tractor) don't mix.  A simple lawn mower repair service area should be able to fix something that small....Alot cheaper too.
  When you get a Real Full Size JD Tractor, come talk to us.

[flyinlow]

A john Deere Mechanic and a Lawn Mower (garden tractor) don't mix.  A simple lawn mower repair service area should be able to fix something that small....Alot cheaper too.
  When you get a Real Full Size JD Tractor, come talk to us.




452 hours.

When I bought the mower the salemen sale ,"well maintained to expect 3000 hours out of it"  .....right  , stuck valve (warranty) ,blown case gasket (common to Kawasaki's, improved one now) and now the drive unit. i cut more grass with a Toro push mower as a teenager than the JD has to do and it was dependable.

I don't see any big Green tractors in my future  Kabota, maybe.

[Guns N Rotors]

I have a GX 325 also. It's a good machine.

You will find everything you need here...

http://www.weekendfreedommachines.com/