The hub that houses the satellites should be carefully examined for damage while the differential is disassembled.


Also check the tooth engagement of the differential and ensure the teeth are not damaged. It is not unusual for tractors to have small chips on the pinion or slight damage to a tooth, but any damage exceeding 1/4 of a tooth should be considered for replacement.


The picture at left shows a Pasquali differential hub. Compare your hub teeth to the picture at left if trying to determine wear.

Pictured at the right are what we call satellite gears. Used in all differentials, the Pasquali tractor tends to show failure of these gears when using the differential lock excessively while turning . When the diff lock is engaged and a tractor is turning, the inner wheel on the turn tracks at a different speed than the outer. If on ice, snow or loose gravel, the inner wheel may slip and prevent damage - but repeated turns with the differential locked will eventually cause failure. The differential lock is designed only for straight pulling and should never be engaged when turning if possible.


Pictured are two new and one good used gear.

Differential Components


Differentials are critical tractor components and when ever the differential is being serviced, consider replacing the bearings. If a bearing fails from lack of lubrication or fragments from a broken satellite, the result could be catastrophic. The extreme pressure between the pinion and crown requires strong support and if a bearing ever fails, the stress could crack or break the case. Major castings are no longer available for older tractors and used ones are rare. Even the cost of the most expensive bearings will appear trivial if you break your case.