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Help with Bevel Gear Box

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Have a Simplicity 990871 with a small leak on the right side where there is a spacer before the pulley for the hydro. I notice that the spacer is loose, free spinning.

Shouldn't this be tight and what is the remedy? Good running tractor, worth fixing.


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I am not familiar with that model but on older models the oil seal butts up against the bearing in the BGB and then shims followed by the spacer.

First check the output shaft for movement in and out of the BGB box. There is a woodruff key on the output shaft inside the box that holds the internal gears in place and they can come loose and allow more movement in the output shaft.

If there is no or very little movement in the output shaft then it may be the pulley are not seated down onto the shaft sufficiently to hold everything in place or there are not enough shims between the oil seal and the spacer to fill up the dead space.

It could very well be just a leaking oil seal which is not that expensive to replace. If I remember correctly when I rebuilt my last BGB for a Landlord 101 the seal cost me $27. which is pricey but not terrible. Your seal is likely a different part number and newer so may be less expensive. There is a good step by step article on rebuilding a BGB here.

Make sure to let us know how it works out.

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I believe you have a 3416H. So it should be the standard large frame BGB.

The spacer should be tight against the BGB ball bearing. The seal rides on the spacer. The spacer is pulled up tight against the bearing by tightening the nut holding the tranny drive pulley on the BGB shaft.

If the spacer is loose, then the seal face is probably running in a different "dirty" spot. That may nick the seal rubber face and even after tightening the spacer up, it may still weep.

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