Variants of a mold are catalogued separately, so each one has its own sets and minifigs. Check these too if something you expect is missing here.

• dupupn0021 Duplo Car Body Tractor this part is a print of it
• 11248c01 Duplo Car Base 2 x 6 with Fake Bolts, Open Hitch End and Yellow Wheels this part is a pair of it
• 11248c02 Duplo Car Base 2 x 6 with Fake Bolts, Open Hitch End and Red Wheels this part is a pair of it
• 11248c03 Duplo Car Base 2 x 6 with Fake Bolts, Open Hitch End and Lavender Wheels this part is a pair of it
• 2312c01 Duplo Car Base 2 x 6 with Yellow Wheels and Open Hitch End this part is a pair of it
• 2312c02 Duplo Car Base 2 x 6 with Open Hitch End and Red Wheels this part is a pair of it
• 2312c03 Duplo Car Base, 2 x 6 with Black Wheels and Open Hitch End this part is a pair of it
• 4883c01 Duplo Car Base 2 x 6 with Yellow Wheels, (Old Style) Closed Hitch End this part is a pair of it
• 4883c02 Duplo Car Base 2 x 6 with Red Wheels and Old Style Closed Hitch End this part is a pair of it