[Vasylb3]

Hi hope someone help me 2008 BMW 328Xi coupe because I have no idea what’s going on with my car. First I heard noises On the bottom of my car and I went to mechanic he said that it’s transfer case and a new one is 3000$ and 2000$ install so I said hell no! I went to buy a used transfer case I took my old one out put back used one from junk jurd with motor and guess what it didn’t worked the noise was gone but my all wheels was locked like you put on truck 4x4 meaning when I tried to turn car start jumping and it was hard to turn with sterling wheel so I took motor out put my old one and same think nothing changed after I was pissed I put my original case with original motor back and it was “okay” again the wheels was spinning how supposed to but case was still was making a noise while driving... so I went back to junk yard gave him back the one I got from him and he gave me the other one after I get home I put new oil witch cost 90$ from BMW and put it in my car with my original motor on it and what happened? All wheels are still locked car is jumping on turns but doesn’t make noise can someone help?