Rule out the usual hiding places first. If the piece really is gone, check the set piece by piece
and leave with the element ID LEGO asks for, or a link to buy the part.
Technic Gear 20 Tooth Double Bevel with Axle Hole Type 1 [+ Opening]BlackPart 18575Element 6346535 or 6093977×2
Technic Knob WheelBlackPart 32072Element 6284188 or 4248204×1
Animal / Creature Body Parts
4 pieces
Animal Body Part, Barb / Claw / Tooth / Talon / Horn, MediumBlackPart 87747Element 6270091 or 4563477×4
Stickers
1 piece
Sticker Sheet for Set 71316-1[No Color/Any Color]Part 26469Element 6151080×1
Tick each piece as you find it, or mark it missing.
When a piece really is missing
Ask LEGO
LEGO takes requests for pieces missing from a new set through its customer service site. The form asks for
the set number and each piece's element ID, the number printed beside the piece in the parts list at the back
of the instructions. This checker lists both.
Mark a piece missing and your list links it to an eBay search for that part, which also covers pieces from
older or second-hand sets.
Keep a record
Copy or download your missing list (the CSV opens in any spreadsheet), or print the whole checklist and tick
pieces off on paper. Your marks stay in this browser, so you can check a big set over several sittings.