I need a little help here with one of these wonderful peerless hydrostatic transaxles.


I'll start with a little history first. This unit is approximately six years old never leaked a drop of oil and worked like a champ until it just stopped, (and I worked it).

While towing an empty trailer to start pre winter work around the house the tractor started to just slow down while holding the pedal in max position. While trying to return to the garage I could smell the belt burning.

Now thinking the belt was just slipping I decided to install a new belt. After careful study of the manual the new belt was installed.

The tractor moved like new for about fifteen feet or so, then the trans axle drive pulley, which is just two pieces of stamped steel bolted together, broke and damaged the plastic fan.


I can't say if the unit hydraulic-ed causing the damage or if the pulley just broke. At this point I started reading different web sites, and I realized I might be looking at a real problem here.

I decided to open up the trans axle and see what happened. There wasn't anything broken, no visible wear or discolored parts. The hydraulic Oil had grayish muck you normally find in transmissions, which I believe to be normal oil break down.

I was able to get and exploded view of a similar transaxle except, that one is of the axial piston design and mine is a radial piston design. The same just different, as the joke goes.

There is a main shaft that has two drilled passages approximately ninety five percent the length of the shaft, the pump end of these passages are plugged with vented plugs. Each drilled passage has a ball and spring captured by these vented plugs. Each drilled passage also has a bleed off hole in it located between the pump barrel and the motor barrel. There are also two machined grooves that are perpendicular to the drilled passage in each of the passages.

These machine grooves allows the pressurized oil from the ID of the pump barrel to flow throw the drilled passages to the barrel of the hydro motor thus pushing on the pistons and the shoes creating rotational movement for the drive pinion and axle.

What is a little confusing is the spring and ball arrangement in this shaft. The springs and balls free float in these passages approximately .150" instead of being held in contact with a seat (back side of the vented plugs), as you would expect a check valve to be installed. These vented plugs appear to be removable however they are staked. I would have no problem removing these, if you think it's worth the effort.

I'm starting to think now I might have gotten away with just the new pulley, fan and an oil change. But you only know what you know, I figured what did I have to loose It was already broke what's the worst thing that could happen? Any help on those springs and balls would be greatly appreciated. Thank you