Tips for a new start

Hi everyone, I want to hear your opinions for a situation at my work. I've been transferred for help in another office in which it's my 3d week. Stayed at the same walk with an older postie that while at start we were getting along fine, I realised he is massively fucking me over. I will explain myself, the guy gives me all the closes while he takes all the ones with lifts and businesses. He would take the car and dissappear while I have a bag full of bundles and parcels. I confronted him and he acts like he is offended and that's the way the walk is (he made it btw) and how he has seniority over me and blah blah. I dont know what to do, the truth is he gets the job done but I can't help feel like he exploits me big time and if i dare say something he wont shut up about how he is in the job all these years and he is the best there and all that. What would you do? Other guys that I spoke in the office say that he is a knob but right now i feel a bit out of place in my 5th week in the job all together and 3d in that office to make a scene with the managera. Thats all, thanks for reading.