2638 HST 4wd Arm Comp snapped off

[Jodo]

Greetings All,

I let a buddy borrow my Mahindra and I get a call from him telling me the 4wd shift lever is loose. Well after inspecting the linkage I see the Arm comp and everything up to the actual lever is gone. The dealer told me they would have to split the tractor in order to repair the 4wd. Apparently, the arm comp snapped inside the transmission/rear axle.

I don't know exactly how it engages the front wheels. Does it spin 90 clockwise and counterclockwise? I was thinking about drilling 2 holes in the "bolt" and making a special tool to rotate it by hand if that's the case.

Any thoughts or suggestions much appreciated. 600 hours on her

 

[airbiscuit]

A picture would help.
There's gotta be more to the story about how it broke.
Is a portion of the shaft still protruding out of the transmission housing?
Could you shift it with a pair of vice grips?

 

[Woodstock Walt]

A picture would help.
There's gotta be more to the story about how it broke.
Is a portion of the shaft still protruding out of the transmission housing?
Could you shift it with a pair of vice grips?

x2. OP, is there any part of the shaft/linkage protruding from the case?

 

[Jodo]

A picture would help.
There's gotta be more to the story about how it broke.
Is a portion of the shaft still protruding out of the transmission housing?
Could you shift it with a pair of vice grips?

He said he was just pulling the lever up like normal and it just snapped. I don't know exactly what happened as I was no there. The break was flush as you can see it is now rusty.

 

[Jodo]

x2. OP, is there any part of the shaft/linkage protruding from the case?

Unfortunately no

 

[Woodstock Walt]

For reference, here is a schematic of the 4wd shift linkage for your 2638:

The illustration allows us to see that it is the actual shaft going into your transmission that is broken. This shaft rotates to shift the 4wd assembly. Unfortunately, I think splitting the tractor and replacing that shaft is your only option for properly functioning 4wd. Sorry to be the bearer of bad news. This is just my opinion, but drilling holes in the shaft and trying to fabricate a tool to rotate it is not going to work. The holes in the shaft won't hold up to the amount of force/leverage required to rotate the shaft, and it will likely just split the shaft.

I'm curious what would cause that shaft to shear. A large amount of force applied to the shift linkage, obviously. But, I'm curious if that shaft was previously rusted/seized in place. Do you shift in and out of 4wd frequently, or is the linkage rarely used?

 

[duffer]

Part #1 is the shaft that broke, if I see your picture correctly. I looked at my 2538 (same drive train), and before I would split the tractor, I would drill the shaft to about ½ of the diameter, tap it, insert a strong bolt, then weld it, then overlay some metal on the bolt, weld it to the bolt, and then fabricate as needed to hook up the linkage.

Worse case scenario Woodstock Walt is right and the shaft splits, or strips out and you have to split the tractor anyway. But I would try this first, and oh yeah...don't loan out your tractor anymore!

 

[airbiscuit]

For reference, here is a schematic of the 4wd shift linkage for your 2638:

The illustration allows us to see that it is the actual shaft going into your transmission that is broken. This shaft rotates to shift the 4wd assembly....

It looks like the shift appendage engages a sliding gear (#6).

 

[Woodstock Walt]

Part #1 is the shaft that broke, if I see your picture correctly. I looked at my 2538 (same drive train), and before I would split the tractor, I would drill the shaft to about ½ of the diameter, tap it, insert a strong bolt, then weld it, then overlay some metal on the bolt, weld it to the bolt, and then fabricate as needed to hook up the linkage.

Worse case scenario Woodstock Walt is right and the shaft splits, or strips out and you have to split the tractor anyway. But I would try this first, and oh yeah...don't loan out your tractor anymore!

Great idea for sure, if it works that's by far a simpler solution than splitting the tractor to replace the shaft. That's definitely the way to do it if the shaft is free.

I'm just concerned about what caused it to break in the first place. Excessive force exerted on it, for sure. But, why? Was the operator who borrowed it struggling to get it into/out of 4wd? Something wrong with the shift linkage internally? Or maybe the shaft is seized in the case from lack of use? If that's the case, then any repair made to the shaft likely isn't going to be stronger than the shaft was originally.

Another possibility is it simply got broken off from a protruding stick or something. In which case, repairing the shaft would be a good fix if possible.

 

[airbiscuit]

The bolt head in this picture is 13mm ((about 1/2"). I'd like to see the stick that snapped off a 1/2" shaft.