Big Mo 500 utility hyd pump drive?

John from NH · Feb 10, 2015

Hi All,
I was moving snow with my Big Mo when the hydraulics went dead as a mild grinding noise started in the top left side of the differential. I checked my parts books and found the drive shaft but couldn't find where it connected to. Looking at the parts breakdown and the tractor it looks like the drive shaft might actually go through the reverse shuttle. Before I started taking things a part I thought I would ask for advice here. Can anyone tell me what the hydraulic pump drive shaft connects to?

Thanks!
John

T.R.K. · Feb 10, 2015

If the sound is at the rear, it is probably the pump coupling, just inboard of the hydraulic pump. I think its 3 pieces, a splined adapter for the pump, a splined adapter for the pto shaft and a sleeve with internal splines that couples them together.

There is also a coupling between the pto shaft and the flywheel that is splined and sometimes the splines strip.
And yes, the shaft goes through the center of the Amplitorque shaft or clutch shaft,whichever your tractor has.

JK2 · Feb 10, 2015

does yours have the hydraulic pump in the center of the back of the rearend or on the top left side of the rearend where the pulley would go?

John from NH · Feb 11, 2015

Thanks for the reply!

After a closer look, the pump is mounted in the center of the differential, slightly off center towards the top. At least that's what it looks like looking down for the seat. Does this indicate anything different or special about the pump drive configuration?

John from NH · Feb 11, 2015

Thanks for the reply!

My Big Mo has a clutch. I hope that will make the repair easier...

Thanks!
John

Big Mo 500 utility hyd pump drive?

John from NH

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T.R.K.

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JK2

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John from NH

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John from NH

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