Car: Audi A4 2004 - 1.8T - Quattro - Automatic Transmission - 86k miles

Background Info: A month or so after getting the A4 I decided to do an oil change, drained the Automatic Transmission Fluid instead of the oil. That wasn't the only screw up, since I thought the ATF was engine oil (looked exactly like dirty oil) I went ahead and added about 4.5 liters of engine oil to the motor, if you're paying attention, that means the engine had DOUBLE the engine oil that it should have, so about 9 quarts or so of oil. At least I didn't mess up the oil type, Mobil 1 0w-40 Fully Synthetic. Drove it for about 2 minutes/less than a block when I finally realized what I have done. Drained ALL the engine oil & changed oil filter/put in the amount of oil according to the dipstick. I also put all the oil I took out that I put in a milk jug back in the transmission.

Around the same timeframe (A week or so) that all this happened I also got these things done to the car: New Battery (Old one literally died on me) and went to the Audi dealership to get the ignition coil recall done, they changed all 4 of them.

Original Thread:

The problem I am having: Ever since the events above occurred I have been noticing the RPM needle shudders/shakes/vibrates/moves/jumps up and down starting on 3rd gear and above (Are these misfires? If they are why am I not getting a CEL?). Happens about every other time when I am going steady cruising or slowly accelerating and reach 40mph. The RPM needle moves about 200 RPM up and down between 1,600 - 2,000 RPMs. As soon as this happens the whole car/cabin starts to drone?/vibrate erratically. To stop the RPM shuddering and the car vibrating I have to either floor the gad pedal (Causing the RPMS to jump up all the way from 2k to 5k RPMs while still in 3rd gear until it changes to 4th) or just let go of the gad so the car stops accelerating.

*Important* One major thing that might help in solving this problem is something that happened to me just this week. The car was doing the RPM shuddering/car vibrating so I usually just floor it to have the cars RPM go up higher, but this time I was SLOWLY pushing on the gas pedal and NOTHING happened. I eventually reached the floor with the pedal and the car STAYED at 40MPH and the RPMs just kept shuddering around 1,800-2,000RPM all in 3rd gear. I listened to the motor and the motor wasn't running louder even though the pedal was floored (This was on AUTO not TIP mode). For someone who knows this problem this might help in solving this problem, In my opinion because of this I don't think it's anything to do with the transmission/engine, but instead ELECTRICAL, or even a STUCK Throttle Body?.

I am also getting NO CEL's of any kind related to this problem nor any CEL misfires although I did log the cylinders once and only got like 1 or 2 misfires, that's all. Only thing that I have gotten as a Break Light Switch error, already changed the switch and problem is still occurring. I have also never gone under "limp mode" (Where my PNRD lights all turn on).

Things that I have tried already:

1. Transmission Fluid Top Off - After reading over 100 threads, I realized it could easily be that the transmission is low on fluid, I went to a German car specialist around the area who has been working on these cars for over 20 years. He topped it off and said there was a good bit missing. He also noticed the ATF was really dark and recommended to drain the pan, clean the pan and change the tranmsission filter for $260 (Me providing 6 quarts of Ravenoil ATF from blauparts.com) The top off only fixed the shuddering when accelerating on a roundabout, still doing the same shuddering above 3rd gear/at 40mph.
2. Air Filter - Old filter was a bit dirty, changed it with a K&N. RPMS still shuddering.
3. Cleaned MAF - Used some MAF cleaner, let it fully dry. RPMs still shuddering.
4. Drove without MAF - Can't really tell if it's driving better or not without a MAF, but regardless, RPMs STILL shuddering.
5. Check for Vacuum leak - Did this using the tennis ball, I did hear a leak around the Oil Filter cables, was pretty small and I doubt that is causing all of this, but will come back to that later.
6. Spark Plugs - I changed the spark plugs with some copper NGK BKR6E's gapped at .032, I know these don't last long and are instead for performance, so I got them to check if this could be it. Car still has the RPM shuddering.
7. Cleaned Throttle Body - Throttle Body was DIRTY as you can see from the pictures. I cleaned as best as I could with some Throttle Body spray cleaner. One thing I noticed is that it doesn't FULLY close, not sure if it's normal or not. I didn't remove the middle circle to clean the ends, not sure if it would make a difference? Did a TBA via Vag-Com (But always freezes before it finished, either way the percentages are 15.6% and 84.4% (Not sure if those are the correct %'s it should be at). RPMs STILL Shuddering.
   
   
   

What I have read that might cause this:

1. Torque Converter - This is probably the biggest cause I found by searching over 100 threads. The Torque Converter isn't unlocking/locking thus causing all this. I really am hoping the TC didn't go bad when I drained my transmission and drove it for a bit. The only thing that is stopping me from believing that it is the TC is that I am getting NO TC related codes/no codes at all. From all the TC related problems I've read, they all included getting a CEL for a code related to the Torque Converter. I've talked to a couple of people and they suggested that if I'm not getting a TC code, to not worry about it.
2. Transmission Control Module Update/Replacement??
3. ECU Update/Replacement???
4. Camshaft Position Sensor??
5. Fuel Pump, Filter, Injectors or Pressure????????

What I THINK it might be:

1. Too much engine oil - I think I added about 5 liters, went according to the dipstick, but then again the dipstick that is in the car seems like a replacement/aftermarket one, so I'm not sure if I can go by that measurement?
2. Unbalanced wheels/alignment???
3. When I put double the amount of oil the engine requires, could oil of gone through other places which it's not supposed to go through? Such as through the Throttle body and into the intercooler? Still wouldn't explain why it only happens above 3rd gear.
4. Front Engine Mount? It's a bit cracked on the bottom of it, but doesn't explain why it happens above 3rd and at/above 40mph.
5. Transmission Mounts?? Again it doesn't explain why it only occurs at the specific times.

I will still love this car no matter what, even if it doesn't get fixed I won't even think about getting rid of it just for this reason. It is VERY annoying though when the vibration happens in the cabin.

Hopefully someone has a solution.

 

The amount of oil and type of oil you put in the engine shouldnt have damaged it. Its actually fairly common practice to add a quart of tranny fluid to the engine the day before a oil change to help break down oil sludge.

You describe this fluctuation as a "surge" or a "vibration".. Surging 200rpm shouldn't feel like a vibration (ie out of balance tire)..

I will almost guarantee that you have a vacuum/boost leak.. Turbo'd cars act way different with a boost leak at speed..

The easiest way to check for a vac leak is to start the car and let it warm up and come to a steady idle. Then start spraying the intake seams with starter fluid.. If the engine idle increases (you'll hear it) you've found a leak..

Remember, a "small" vac leak at idle is a "big" boost leak at speed..

Be sure to check all the rubber hoses as they're prone to dry rot.

 

I have the exact same problem in my '06 A4. Car vibrates and tac surges (RPM needle moves about 200 RPM up and down between 1,600 - 2,000) at steady speed about 40 mph and light pressure on accelerator. Took to Audi and they told me I needed a torque converter. Told me to keep driving as it was not that bad yet. Told me it would be about $3000 to replace. I think i will ask someone to check and see if i have a vacuum leak prior to replacing the torque converter. I also note that it is much worse when the car is cold.

Side question, I had my transmission seal (between drive shaft and transmission, when the car was under warranty, does anyone know if that seal being bad could have caused my torque converter to go bad?

 

My problem turned out to be that my transmission fluid was low. I took it to a shop so they could fill it but it still happened after that. When I got home I took a look at the car and I noticed that it was STILL low on fluid. I added some fluid myself after and it worked. I suggest getting a good shop or the Audi dealership to so a transmission fluid flush and also to change the oil filter on the transmission. They will have to drop the pan to change out the filter. Then when they add the fluid in they have to do it right.

Car works great now.