Two speed modification for PT 422/425

[toolz_not_toyz]

</font><font color="blue" class="small">( From a steering point of view, it would only make sense to series-connect the wheels on the same side of the machine. When they are connected this way, they are forced to spin at the same speed (disregarding inefficiencies and bypass leakage in the motors). )</font>

Your logic is correct. And for a vehicle that is designed to operate on hard surfaces and expected to spend most of its time on hard surfaces that setup makes sense. But for a tractor? Keep in mind that many offroad vehicles are not designed to operate with a locked differential or locked hubs on hard surfaces either for the very same reason you have just pointed out.

 

[stray]

I hope this explains the routing and positioning of valves and hoses. This should work like it's drawn but I am hoping to refine it further. The blue and purple lines will only be in service in the high torque low speed mode. I was thinking of using a couple of $66 log splitter valves because of cost but they are large and operate manually. Can someone please put me on to some good cheep solenoid valves?

 

[J_J]

Stray, Check out Ebay

Item number: 7564005851

Electric solenoid valve.

 

[stray]

It looks like two of those will work. are two available here?

 

[J_J]

Stray, There are probably more than one, just email the guy and ask. Make sure you get the 12v ones. Or just type in hydraulic valve in the search window on Ebay. I got four sets of these valves for my backhoe project, but haven't decided whether to use manual valves, or the solenoid. Solenoid valves are instant on, while manual valve can be slowly activated

 

[stray]

Thanks abunch JJ. Will do.

 

[Rip]

RegL, Sorry not to have gotten back sooner. I did the swap as soon as I got the used machine back in early '04 so I can not say "how much" difference it made, but by the numbers I cut max speed by about 1/2 and got about 55% more torque.

Max speed is probably in the 8 to 9 MPH range and I use all of the available torque on the steeper (30 plus degree) slopes (read rocky Rocky Mountains) on a regular basis. It meets my needs and I am pretty sure it would not have in original configuration. Could I use more speed or torque? Sure... more..more...!!

 

[toolz_not_toyz]

Check out this place for solenoid valves:

Surplus Center

 

[stray]

To set up you Pt like this schematic one will need 8 new hoses and be sure that the tank port is pressure rated and see that the valves are rated with enough flow.

 

[stray]

Route the test block or a block with the solenoid valves like this. This would be the high torque low speed mode.