Transmission oil pressure dash light

[ramonajim]

Recently acquired a Montana 3840, and I'm in the process of catching it up on maintenance.

The transmission oil pressure light is on - constantly.

I've changed the filter (with a Wix) and brought the level back up to midway on the dipstick. I haven't done a complete fluid change (wanted to see if the issue was a plugged filter first).

Any suggestions y'all might have in terms of getting to the reason the light is on would be greatly appreciated.

 

[Lgim]

You got me stumped on this one. I don't think there is a trany oil light, unless I'm totally wrong on what tractor you have. I'm assuming it is a shuttle shift with 4 forward gears and 3 ranges. I was told that a 3040 (what I have) and 3840 were the same tractor except for the horsepower the engine put out. Are you referring to the Gear light on the right hand side of the dash that lights up yellow/orange?

gary

 

[ramonajim]

I've bought the user's manual (it's actually pretty entertaining - not overly useful, but entertaining ).

It labels the idiot light in question as Transmission Oil pressure in the table of symbols, and as Hydraulic filter warning lamp in the instrument panel legend.





And yes - you are correct. It has a shuttle shift with 4 forward gears and 3 ranges.

 

[Lgim]

I would have to say Hydraulic filter then. Oil pressure would make sense on a hydrostatic drive where you have a pump driving the transmission. On ours the oil is sucked from the tank through the filter to the pump and then to the hydraulics and then back to the tank/transmission. the gears only run in the oil and whatever gets splashed up lubricates the gears.
As far as I know the only bypass for a plugged filter is in the filter itself. I have a repair manual for it but I cleaned up my office and haven't seen if for a while. My guess would be that a electric error / shorted wire or something in the dash rather then a plug in the hydraulic system assuming the hydraulics work and you have a new filter.

As for the owners manual I had to get my wife to read it to me with a Korean accent, then I could translate in my head what they were trying to say. (sorry I know not politically correct).

gary

 

[ptsg]

Is the filter on the suction side of the pump? If that is the case, be aware that some filters are made to be used on the Return side, therefore they have a check valve on the filter itself. If this filter is used on the suction side, it will prevent the pump from pulling oil and can cause the pumps to burn.

Are all the hydraulic functions working 100%?

 

[Lgim]

I found the Service Manual I have. The only reference to the filter is to say the oil is filtered before going into the pump, and that the entire system is protected by a Relief Valve.

No reference to this light at all

My only other thought was perhaps the light is indicating the oil in the Hydraulic system has too much pressure or that the Relief valve is adjusted to the point that it is never going to relive the pressure and therefore the light is on all the time. If this is the same tractor that had the broken loader mount I could see the previous owner doing something to get more lift.

I guess the question is what is the light connected to

gary

 

[ramonajim]

Found two likely sensors - one right at the filter mount. It measures a dead short from the sensor pin to chassis ground.

Dash light stayed on with the sensor wire unplugged.

Plugged the sensor wire back in - and the dash light is now off.

Not sure what to make of this data.

Hydraulics seem to operate as intended.