3850FD Won't Move

[FlyingArmadillo]

Hello and thanks for reading. I'm a few months into owning my first tractor and find myself begging for help as I'm running out of options. Here's the skinny...

I've got a 3850FD that is stuck and will not move in any gear. PTO and all hydraulics work fine. The problem started a few months ago and the more we began to use the glow plug warmer the worse the issue would become. Basically, the tractor will run fine but suddenly you won't be able to move it. You can row the gears without depressing the clutch. The first time it happened I figured clutch issues but it continues...

We have had a loose ignition cylinder since purchasing the tractor. After using the glow plug warmer more in recent months we've noticed the "lack of movement" issue becomes more frequent. Sometimes, however, after tightening the cylinder, or holding it while turning the key, the tractor would work as normal. The problem was very intermittent. But now it's stuck. The same thing happens when you're driving the unit and you bump the key from the "on" to "off" position. Without pulling the kill switch you still have power, just no transmission. Turn the key back to the right and all is well...at least it used to be.

Following my incorrect diagnosis I just replaced the ignition cylinder. It was zero help. Tractor is still stuck in the field. I can't for the life of me find a service manual or a mobile mechanic to come service it.

Any advice would be VERY much appreciated!

 

[mddorange]

:welcome:
To the forum. I am sure one of the great people here will be able to help.

 

[FlyingArmadillo]

:welcome:
To the forum. I am sure one of the great people here will be able to help.

Thank you and I hope you're correct!

 

[skylarkguy]

I'm not familiar with your particular model but it sounds to me like you have multiple problems. I can't imagine that the ignition switch would cause it not to shift. Unless there is some kind of electromechanical safety device or something. I know on my tractor sometimes when I get off I kick the "high/low" range selector to somewhere in between. Then no gears work until I select either hi or low. You might consider checking the position of all the gear selectors, then carefully noting when it works or when it doesn't.

 

[FlyingArmadillo]

Thanks for the feedback skylarkguy. Unfortunately I've tried switching between 2 and 4wd numerous times, along with checking the diff lock, pto, etc. All to no avail. I know the ignition sounds strange but I'm at a loss. It was the only thing making an impact when I had the problem in the past.

 

[284 International]

Whereabouts are you located?

I understand that there may seem to be correlation between the key switch and the ability of the tractor to move, but there really can't be. My understanding of this model is that it is a conventional stick shift transmission with 3 ranges. This is entirely a mechanical connection between the flywheel of the engine and the drive wheels and PTO output.

How do you know the PTO works? Are you able to apply power to an implement like a tiller or mower?

The hydraulic pump works directly off the engine, so while it's good news, it just means the engine runs and the hydraulic pump and system is operable.

The potential options are, essentially, these:
1. The clutch is bad/out of adjustment/slipping.
2. There is a gear or shaft in the transmission assembly that is either out of place, broken, or somehow disconnected from where it should be.

Since it won't drive in 4wd, the rear end, final drive, and axles aren't the issue.

If you can shift gears with the engine running without any grinding or clashing, either the clutch isn't connecting to the flywheel, or the gearshift mechanism isn't moving the gears themselves.

Let us know about the PTO situation and verify that there is no grinding of gears when you try to shift gears with your foot off the clutch and the engine running.

 

[FlyingArmadillo]

I'm located in central Texas, just south of Austin. I'm puzzled by the electrical versus mechanical aspect of this as well at it makes zero sense to me.

You are correct, the PTO does run the mower. The faulty clutch was my first thought but it has never slipped, smoked, or given me any sort or problem. I can row the gears without depressing the clutch which does confirm this could be the problem I suppose.

If there is any further feedback I can provide please let me know. Thanks for your help!

 

[284 International]

While purely speculation, if the mower will actually receive full engine power through the PTO, I would focus my attention on the shifter or affiliated parts.
While not a Mitsubishi, the basic arrangements of this style of tractor will all be more or less the same, so the diagram may be at least a little bit useful:
Yanmar Tractor Parts: TRANSMISSION_INTERNAL

On this particular tractor, a Yanmar YM2000, the transmission shifter mounts in a plate that bolts to the top of the transmission and carries the shift rods and forks with it. (This diagram doesn't show the plate that the rods [#17, 18, 19, etc] fit into)
Yanmar Tractor Parts: SHIFT_LEVERS

If you aren't familiar with how the transmission functions, starting at 3 minutes of this video there is a good explanation: https://www.youtube.com/watch?v=aFvj6RQOLtM

There are other good videos too, but that clip provides an overview of a non-synchronized straight-gear transmission that will look a lot like what you see.

I would remove the top cover and see if any shift forks, gears, or other components are broken or damaged. I have experienced a broken shift fork before, which left the tractor functionally in neutral, with no way to select a gear.

If you start the tractor with the clutch in, engage the PTO, and suddenly release the clutch to spin the mower, is there any indication of slippage?

 

[Snead]

Not sure if any of this helps but thought it may be some good info:

Based on a previous post (Link_1) I think you may be able to use a MTXXX manual instead of the 3850 (Mitsubishi Gray to MTXXX Manual Link_2) Also I put some other links below which may or may not be of help

Possibly Related:
Link_3

Future parts for the D3850FD:
Link_4

Parts Manual K4C-12A D3850 (FD):
Link_5

Model Type Ref:
Link_6
Link_7


-Snead