LEGO Juniors Vehicle base "Lift Kit"
The vehicle base assembly that comes pre-assembled in some LEGO Juniors sets is not intended to be disassembled. But if you are not a child between the ages of 4 and 7, cutting and filing off only the little plastic nubs (keep the tubes intact) that keep the separate pieces assembled opens up new possibilities for this LEGO piece. All you need is a "Technic, plate 2x8 with 7 holes" (part number 3738) with holes as shown in the pictures below to accomodate the tubes/shafts. DO NOT cut the tubes off; they help hold the plate by giving the plate additional points of contact, therefore increasing the "clutch power" (LEGO technical term) between the pieces. This is why I am using a plate with holes. From there, you can put regular plates or parts as you wish.
(Click on each picture for a full-size version):
Here is only one example of the possibilities this opens: a "lift kit" for your LEGO vehicle (Click on each picture for a full-size version):