747 Diffential tech-tip; prevent leaking diffs
When assembling the differential of the 747, it may occur, when you fill up the diff with oil, some oil enters the holes for the screws that hold the differential together. As a consequence you may have a problem, because you cannot tighten the screws enough due to “hydraulic lock” and the diff will leak oil.
We recommend to drill the 4 holes with a 2.0mm drill all the way through according to the pictures, so the oil can escape from the holes if needed. ( make sure to work safely and wear protection as needed ).
In general make sure not to overfill the diff. When there is too much oil in the diff, the chances that it starts leaking are big, as you cannot tighten the screws as far as needed, or even bend the diff-case.