Differential lock doesn't work?

[California]

This is the first clear picture I've ever seen showing how the YM differential lock mechanism works. I thought others might be interested.

I'm linking to relhogh's picture here, he posted it in his thread about repairing the brakes on his YM1500D Green.

The way the difflock works is sort of Mickey Mouse. Push the pedal under your right heel, that rotates the shaft going into the transmission. This forces the doubled rollpin to climb the ramps of the shifter fork. The fork then forces the diff lock collar sideways, engaging its pins into the recesses of the gear next to it.

This is notable to me because my YM186D needed this repaired before I put it in service. That ramp was worn away where the rollpin meets it, I think because the tractor was used for a couple of decades clearing snow and the operator was on the difflock pedal all the time. Welding some metal on the ramp (then grind/polish) to restore its shape was all it needed, now it's good again for many years.

And here's the badly worn ramp on my YM186D before repair.

 

[k0ua]

Hey thanks for posting.. Now I know how that works.. I bet they are all about the same or nearly the same, and your description was good also. Again thanks.

James K0UA

 

[Pete Judd]

Thanks Cal, I know that I have a sheared roll pin on mine, and the pic lets me know what I am going to get into when I finally get around to fixing it.

 

[relhogh]

Hey California

Yea that also works it you pull up on the lever.
Dont know why they made it that way.

 

[chriswheeler]

Noticed mine when I had to pull the final drives out of my JD 950, same setup, yanmar made. Have to remove both left and right final drives to do anything with it. Drive for the right wheel ( dif lock ) is engaged by moving a coller when steping on the dif lock. This coller is spring loaded with 2 drive pins for the right wheel. When engaged, friction from the load on the pin drive keeps the drive pins in place. The moment that the load is off the pins, the spring disengages the drive unless you are still standing on the pedel. Almost fool proof, but the left wheel has to rotate some for the pins to engage the drive. I was that deep into mine to change a bad 3rd gear cluster, almost had to strip the whole case to get to it. Not much fun to work on.
Chris

 

[ym165dpete]

On my ym165d the shaft going through the finder was seized up . when I did my referb and paint ,it took a good long while to free it up.

 

[California]

Someone asked about the photo I included in the first post above. Something has gone wrong in the TBN database and old photos are no longer visible even though I can see this photo listed in my own Attachments history.

So here's a fresh link to show the same photo. I'll note I first posted it 3-29-2011 so that I can find it again if this link goes bad.

Pressing the difflock pedal pushes a rollpin against this ramp as described in the first post above, eventually causing the wear you see here. The previous owner used this YM186D mainly for blading snow. He must have been on that difflock pedal all the time.

Welding the fork back up and grinding it to its original shape restored the difflock function.

View attachment 422684

The fork is #85 in this Hoye diagram for YM2000. The V is hard to see but the double rollpin that bears against the V is obvious. Stepping on the pedal causes the fork to slide along the shaft that passes through it.
Yanmar Tractor Parts: TRANSMISSION_INTERNAL

 

[smitty888]

@California, could you please repost those pictures again? I am needing to do this repair on my tractor, and I'd like to see what you did to yours. Unfortunately, the site says that they are no longer available.

Thank you!
-smitty888

 

[California]

They've been messing with the old archived stuff again!

I found the photo is still listed in my 'Attachments' and it was used in this 2011 post. Tell me if the photo and diagram are visible to you at this link:

Trans case lock seem not to work anymore

A few months ago It worked great when I had to cross one of my creeks, today, I had one wheel slipping and stomped the pedal, and it did not engage. I have not gone to the manual yet, and it was getting dark, the pedal stayed down and had to pull it up with my heel. Any thoughts? This is on a 186D

www.tractorbynet.com

The repaired shift fork is #12 in the diagram, and the worn area built up by welding is near the line drawn from '12' to the part.

Here's my photo again - before the worn spot was filled in by a weld.

 

[ponytug]

The photo and parts image are visible to me...