How big of a chunk did the tooth break? I really can't see it in the pic. Look closely at the break. Is there some dark colored, then fresh, clean, broken metal coloring? If so, a crack has been there for a while. A good PT (dye penetrant) test or mag particle on the rest of the teeth would be really interesting to see (any more cracked teeth that hasn't broklen off).

Don,

This picture is from the last gearbox inspection which was December, 06.

I havn't actually seen anything from this box but expect to get access to everything and will check the pinion with dye penetrant like you suggest.

Danny,

Why would not you draw a little diagram including gear box internals of the power train showing:
-direction of axial thrust exerted by the mixer,
-bearing types in the gear box (indicating fixed one and floating one),
-gears arrangment and types (spur/herringbone),
-coupling types,
-motor (with bearing types).

I am leaning (as does Rusty) toward axial thrust which overloaded the spur gear causing tooth fatigue failure in a snap-up manner). The diagram may help to understand that.

Also.. Last reading is taken on June 1st. Was the broken tooth discovered same day in the afternoon (June 1st is Friday) and by what symptom?

Dave

This message has been edited. Last edited by: David_G,