Hey there all. I have just recieved 8285 tow truck & am currently building it. I have noted in the instructions & on the bricklink inventory that there are 29 axle jointers. Part number  6538b but my set has 6538c in its place. Yes they both do the same job. Is this a normal change? Are there others out there with the same? Also my set has most of the metallic parts but the wheels are blueish gray. I know there were a few versions of this set. Are all 10 wheels meant to be the same? My instructions have the glint on all the wheels & tank parts.