Hi, so I own a 2003 325ci. Before my questions, I'll explain the problem to the best of my understanding. Just two days ago, I brought my car to an independent shop Bavarian motor experts (BME) for a routine oil change. They put my car on the lift, and begin a full inspection of the vehicle, during which they find a supposedly rare issue with my differential; The back left axel was popped out from the differential. They said there's a ring shaped piece that's missing, which is suppose to hold the two together. They suspect it may be inside the differential, but it would cost $550 just to take the cover off and see what might be wrong inside. They decided to go the cheaper route of pulling the axel out to inspect that for the missing piece. The mechanics determined that my only option was to schedule for another time that they could open the differential to find the problem(I overheard the manager telling the
mechanic that they didn't have time to deal with this problem on that moment), so the mechanic told me he would put the axel back as it was, which was described as really unreliable, and could fall out at any given moment. I was very hesitant for them to doing return the car to it's previous state, especially after its been taken apart already, but I agreed because the mechanic seems very honest. He came back after a while and said they were not able to even put it back into place because of the groove or whatever part the female part of the differential is called, was worn and gone?
I had to leave my car there and have it until Tuesday at the soonest, and that's only the mechanic found a used differential, or I pay for a new one, which was quoted at $2000. I've searched using car parts, and found a few different options, but none are opened on the weekend to call so far. My questions are:
1. How much can I expect to pay for shipping (to Honolulu), and for a used differential assembly.
2. My main source of info has been http://www.bokchoys.com/differential/Where.htm
I also read that a differential can increase torque, so would I be able to use one from a 330i/330ci, so long as it's from a manual transmission?
3. Finally, what Other sources(online or in Honolulu) are there to search for a new differential?
I'd appreciate any help. I really don't know how I'm suppose to handle this at all tbh.