X5 problem with tbs,asc lights

[Doonbugg]

Hi everyone. I hope the vast knowledge in this group will help me figure out my problem. I have a 2005 X5 with the 4.4. It started throwing a 1434 code. I checked it and then an emergency came up and I had to take a short trip in it. On the way back the TPMS light came on. I stopped and had all of the tires checked and they were all fine . Them a few miles more and the ASC light came on. Still running fine. Just before I got home I thought I heard it giving a little grumble from the front transaxle area. I took it to an independent garage today and all they could tell me was It was the secondary air pump. My question is, what would this have to do with the transmission ? Any clues would be appreciated.