TC35D Hydro Hi/Lo shift problem

[Gurney10]

I recently bought a used TC35D hydrostatic and the electronic hi/lo shift is in the low side and would not shift to the high side. I had hoped it was just the switch but I replaced it and still have the same situation. I don't think it is in the relay because I switched some of them around and it didn't make any difference. I am now thinking it is the solinoid. I have had a number of the TC hydro's but have never experienced this. Any suggestions?

 

[jinman]

Look under the left side operator's platform and make sure that hoth wires are attached to the solenoid. Most times when your problem is seen, it is because brush has pulled a wire loose from the solenoid.

 

[jinman]

One additional thing. . .

If you turn the key to run, but don't start the engine, the rabbit/turtle switch should work normally. You should be able to put the fender switch in rabbit and see that the light comes on and stays on. Then, you can unplug the wires going to the solenoid and check for 12vdc with a meter or test light. If there is 12v when the switch is in rabbit and 0v when the switch is in turtle, then you can suspect the solenoid, but otherwise it is a problem with the circuit other than the solenoid. BTW: I have never heard of that solenoid failing. Yours would be the first I ever heard of. In the past, it has always been a disconnected wire or malfuntioning switch or relay.

 

[Gurney10]

Thanks for the replies. I dug a little deeper last night, and the rabbit switch will light but it does not hold, so apparently there is a circuit problem. The switch will hold in the turtle position and the transmission is in the turtle range. I tried touching a hot wire to either of the wires going to the solenoid, but nothing happened, so thats what makes me think there is a problem with it, and I could not sense any fire on the either wire coming to the solenoid with a tester.

I am going to try to talk to the shop foreman at the local NH dealer today and see if he has any suggestions.

 

[Gurney10]

I now have it working, since I got the right combination on the wiring. However, it will switch the solenoid to the rabbit side but the switch will not stay in that position. As soon as I let go of the switch it goes back to turtle. Could that be a relay problem? Any suggestions.

 

[jinman]

Normally, if you have a loader, you have a set of rabbit/turtle switches on the joystick and one on the right fender. If either switch is malfunctioning, it could be sending a constant turtle signal so that as soon as you release the rabbit switch, it goes back to turtle. Of course, it could also be the relay. I'm on the road and don't have my schematics in front of me, so I can't tell you exactly what to check, but I'll be back home by Sunday and try to update my response.

 

[Gurney10]

Thanks, I don't have the loader joystick rabbit/turtle control, so it will have to be in some other area.

 

[jinman]

If you take your left side cowling off, you will find the relay assy as shown below. The relays labelled 1 and 2 in the illustration are the rabbit and turtle relays. I'd swap them out to see if the problem changes because they are identical relays. If the problem stays the same after swapping, this is not your problem.

 

[ArtMech]

In some cases, when there is a malfunction of more then one electrically controlled issue on a machine, it may lead to the earthing connection failure, which might be common to those issues. If You have a multimeter, check resistance and circuit continuity of the earth wire concerned. You said You touched the hot wire? The wire heat comes on because of increased resistance in a circuit. The resistance increase could be caused by bad earthing.
Find earth connection location if You have wiring diagram. It could be loosen or rusted.

Not sure if it could help

 

[jinman]

In line with what saracenas said, even though you do not have a joystick with the rabbit/turtle switch, the wire harness and connector are there on the tractor but connected to nothing. If something happened to the connector to cause a short, it could also be a problem even though you do not have a joystick switch. Make sure the harness wires and connector are secured in a safe place away form chafing and damage.