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 Axle Connector 2 x 3 with Ball Socket, Open Lower Axle HolesBlackPart 93571Element 4610948×1
Technic Axle and Pin Connector PerpendicularBlackPart 6536Element 6261371 or 4173668×1
Technic Axle and Pin Connector Perpendicular SplitBlackPart 92907Element 6279021 or 4610371×2
Technic Pin Connector Hub with 2 Pins with Friction Ridges Lengthwise [Big Squared Pin Holes]BlackPart 87082Element 4560174×1
Technic Bushes
3 pieces
Technic Bush 1/2 Smooth with Axle Hole Semi-ReducedLight Bluish GrayPart 32123bElement 6271165 or 42115731 spare in the box×3
Technic Panels
2 pieces
Technic Panel Fairing #21 5L Small Smooth, Side BTanPart 11946Element 6121107×1
Technic Panel Fairing #22 5L Small Smooth, Side ATanPart 11947Element 6121172×1
Technic Beams Special
1 piece
Technic Beam 1 x 3 with Ball Joint in MiddleDark Bluish GrayPart 98577Element 6001085×1
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.