Bock120

Hi, I am new here and a first time Audi mechanic. Working on my son's girlfriend's car. It's a 1998 Audi A4 Quatro 2.8l. The issue started when out of the blue reverse stopped working. All forward gears worked and the vehicle wasn't in limp mode. The TPS seems to be fine because the car won't start unless it is in park or neutral. From threads I read I figured the problem was the TCM. The floor board was full of water, so I cleaned the up and we ordered a used TCM. I made sure the replacement had the same serial number before ordering. When it arrived I plugged it in, reconnected the battery, and all seemed good. As soon as I put the vehicle into gear there was a loud "POP" from the unit and a little smoke and now something inside rattles, and the car went into limp mode, all forward gears worked but still no reverse. I have attac hed pics of the original TCM and the purchased one. I did use VCDS lite, the free version, and codes were just very generic. I can provide them if needed. If anyone can provide me any guidance I would really appreciate it.

Original:



Replacement:



Thanks for all your help.