There are two cool things about this truck, first you cannot gain stars.
Spawn FBI Buffalo Dial "2275550100" on the cell phone.
For some who don't want to look on a phone, and since some tv's have bad graphics and you can't see the letters, well here they are.
A, B, C=2 D, E, F=3 G, H, I=4 J, K, L=5 M, N, O=6 P, Q, R, S=7 T, U, V=8 W, X, Y, Z=9.
In order to unlock a friend's special ability, you must have a high 'like stat' for that friend, and this stat is based on how regularly you hang out with your friend.
Call your friend and perform activities with him on a regular basis to increase your 'like stat'.