check engine light comes on and three mechanics all say i need new torque converter even tho i have no symptoms as yet. Will I get symptoms eventually, or could this be an electrical issue. When they turn off the warning light, it takes a day or so to come back on. There has been no reduction of mileage, no gear slipping, no problem accelerating.
Did the mechanics read the codes associated with the CEL, and what were they? If it’s not on your estimate, you can get the codes read at a chain auto parts store for free. Call before you go to make sure they have a code reader that works.
When you took it for the 2nd and 3rd opinions, did you mention the first diagnosis? That could influence the answer they give you. Also, how did you find these mechanics? If it is from friend’s recommendations, that’s great. If not, ask everyone you know who does good work and try them for another opinion.
There are a million reasons the MIL (check engine light) will come on especially in cars from that timeframe. The “torque converter” error is pretty common and usually means nothing. The transmission valve body is flawed on A4s and A6s from 2002-2004. There is a valve that is too big. Even getting it replaced just means the light will come on less often. If you just have the intermittent MIL (it comes on after about 100 miles of being reset and goes off and on every so often) then its just a electrical issue. I imagine that most people make the mistake of trying to have the TC replaced, based on a 2 minute OBD-II diagnostic.
If you actually have symptoms (gears slipping, limp mode, wont go past 3rd gear) then the car is doomed. If no symptoms of transmission problems, I would save the money and have your all your gaskets done, (these cars are very leaky), and get a jumpstart on your Control Arms (that clunk will only get louder).