SEALED BEARING for Main Gearbox Output shaft

[Tang_Killss]

Sealed bearings are designed to be maintenance-free and come pre-lubricated. Removing the inner seal may allow the bearing to be lubricated by the gearbox oil, but it's essential to ensure that the gearbox oil is compatible with the bearing and provides adequate lubrication. Insufficient or improper lubrication can lead to premature bearing failure.

[Joker_Bones]

Are you differentiating between sealed and shielded bearings?

Shielded bearings with the metal shields are not sealed, my understanding is the shield(s) are intended as a deterent to the ingress of unwanted external matter and may be removed for applications where this is not required.

The gearbox bearings discussed in this thread are ball bearings. If originally sealed or shielded, are you suggesting gearbox oil may not a compatible or adequate lubricant?

What is the link intended to show?