Hydraulic Pump Adapter Assembly with Gear, Lycoming 540 Series 71675, 71676.
This adapter was purchased as "used" for a project involving the installation of a B&C backup alternator (standard vac pump drive) to an IO540-C4D5D engine. Unfortunately the -C5D5D is not compatible with this adapter. Lycoming were completely useless... the adapter will fit most of the -C engines but but the -C4D5D.
It has been paint stripped, pressure cleaned, dye penetration NDTd, repainted with Lyco paint, has a new oil seal, and there is no apparent wear on it. A new gasket is included. The oil feed hole to the hydraulic pump end has been plugged with a grub screw, which is the correct thing to do if driving an accessory that doesnt need oil (an alternator or a vacuum pump). No paperwork is included so you may need an A&P to certify this part.
Please note the P/N is either 71675 or 71676. It isn't obvious which one it actually is. You need to refer to the photos and to the PDF manuals above. I suspect one of those two part numbers doesn't actually exist, but Lycoming were unable to communicate usefully on the subject. The casting has "75176" cast on it.
PDF from engine MM
USD / GBP / Euro 150 plus shipping