It beats me. If you don't get response here, try forum406: Gear & Pulley engineering

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(2B)+(2B)' ?

What exactly do you think is strange? You posted a number of photographs, but expect people to guess at your problem.

TTFN (ta ta for now)
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I have seen this pattern (especially last phot) with greater wear spots at end of teeth caused by a gear natural frequency (confirmed by impact test) where the vibration mode was a wobble of the larger (bull) gear.

Walt

Your Welcome for Thanks or feedback in advance!

Walt

Hi,

Based on the contact pattern, i would recommend you to check for the axial play in the bearing. I hope the gear is mounted on a set of taper roller bearings. Kindly ensure that the pre-loading in the taper roller bearings are fine. I hope that this should solve the problem. Further, I feel that there has been an initiation of micro pitting in the gear flank. Kindly check for the viscosity of the oil and also for the presence of any abrasive/metal particles in the lubrication oil.

Regards

K.Kaarthic

it appears from the photos the helical pinion has excessive wear,
some suggestions
attach a magnetic base with a dial indicator on ground surface, and look for excessive runout.
could be a worn bearing , or miss alignment.
a rebuild of this gear box is required, the pinion gear is worn.
the vibration is the teeth interfering causing excessive wear.

a full failure analysis will be required, a qualified engineer or technician or both, will have to
tear down the box and document and take pictures of each component.
document were and how the failure occurred.

Apparently the OP is not interested, since it was posted Feb-11.

Walt