Proper operation of Hy-Drive tranny.

[Melvin1944]

I am considering purchase of a 446 or 448, but don't know what to look for in the operation of the Hy-Drive. I drove a 446 last night and all I could get from the Hy-Drive was 2 speeds in each of the 2 axle speeds, consequently 4 different ground speeds. In reading about the trany it says it has "infinite" speeds in each of the 2-speed axle ranges. I was expecting performance like a hydrostatic. Is that the way this setup is supposed to work?

 

[hydriv]

The lever on the left side of the steering wheel controls the volume of oil flow to the hydraulic drive motor. How well that works is dependant upon many factors.

- the wrong oil may be in the system

- the mechanical linkage between your hand and the travel valve that controls the oil flow may have a lot of wear

- the hydraulic pump may be badly worn.

- perhaps it's a combination of all of the above.


The last 400 Series tractor was made during the 1988 model year. Many of these machines are now owned by people who don't maintain them or repair them. They just use them until problems begin to surface and then they sell them.

Like all things "used", you should expect that there are issues that need to be addressed. You will have to spend a bit of money along with your own time to correct the wear and the dumb-*** mistakes but all of the problems are minor and fairly simple to take care of.

The big issue is "PRICE".

What matters here is the overall condition of the tractor, the options it may have and the attachments that are part of the package. Condition of the engine is also important, especially on an Onan-powered machine because of the cost of rebuilding that brand compared to one with a Kohler.

Since you are currently looking, you should try out a few other Case or Ingersoll tractors so that you can make comparisons in how they drive to this one. The Hydriv system is somewhat different to the feel of a hydrostatic drive machine but they both provide infinite ground speed when they are working properly.

 

[Melvin1944]

Thanks Hydriv. Since I am new to the Hy-Drive system, I just needed to know what to expect from a unit that is working properly. So you are saying there should be a gradual increase in ground speed as the flow control lever is moved toward a faster speed setting. The one I drove, the flow control lever had a "notch" that was slow and a "notch" that was fast and no change in speed between the notches.

The notches I refer to actually were stopping points for the flow control lever. I expected the flow control lever to have a smooth travel from slow to fast without these stopping points. Does that all sound like it should operate, or is there a problem here?

Thanks again Hydriv!

 

[hydriv]

Just below the dashboard where the Travel Lever passes through it, there is a nylon block that serves as the Neutral Safety Switch as well as having serrations and notches to hold the Travel Lever in whatever position you want it in.

However, in spite of the existence of the notches, there should be a smooth increase in speed from the moment the Travel Lever is advanced from Neutral in either direction. There is obviously a problem with this tractor if it is doing what you say it is.

This is why I suggested that you test drive OTHER Case or Ingersoll tractors so you can experience them. With any kind of luck, one or more of them will be in good repair and allow you to experience the hydraulic drive system as it should be.