ATF Overheating Audi s6 2007

A6 All/ S6 All
#1

Hey guys sadly to say the transmission is overheating i thought i fixed it from last time of last year since it stopped but i guess not it into went limp mode and cut off on me on the highway at like an hour of driving. The code was like internal control module temperature too high. I changed the transmission fluid 2 times already and the transmission isn’t showing a code for a solenoid or anything.

Does anyone have any idea what it could be. Could the lines to the transmission cooler are clogged on the transmission side. i did check the coolant side and they seemed to be flowing through freely.

I completely have no idea at this point i’m considering taking it to the dealer and maybe there scanner could figure out what’s wrong with it or maybe they can figure it out.

This been plaguing me since 2020
If anyone has any idea it would be very helpful

#2

I sprayed the water hose on one of the cooler and it immediately started going down

#3

Maybe replace the cooler? If that doesn’t work, I’m not sure. Last time my transmission put the car in limp mode, it ended up being the mechatronic unit failing. Good luck. Best wishes.

#4

Realistically it could be that cause this is a auction and they totaled it out with a clean title maybe this is why they totaled it out

#5

Anyway I was thinking couldn’t I make a separate cooking system specifically for it.

So you know the cooling of antifreeze that goes around the car at a high temperature but what happens if i separated it to its own antifreeze cooled

Like custom radiator to I guess coolant pump and to transmission coolers and back

Wouldn’t the antifreeze be cooler

Because I noticed when I sprayed the water hose it started dropping so perhaps if I make the antifreeze run at a colder temperature maybe I can compensate to stop the over heating

#6

Did you ever check or replace the thermastic coolant hose that goes to the trans? It is right under the bottom of the bell, coolant hose with a weird plastic thing in between. Iirc connects to the electric wp

Did you ever confirm the aux trans electric WP is working. You can test in vcds output and it will cycle that pump and you can hear it

Forgot where u left off…

#7

The aux pump is definitely working I changed it to a new one

the thermostat I checked before and reinstalled the thermostat should I remove the thermostat piece

#8

I would. I replaced that hose and it was like 200 bucks!

#9

Okay I’ll remove that shit and also I’m at 99c I sprayed some water no real change when I did it yesterday the car was off and it dropped

#10

Okay the transmission fluid temp jumped from 102 to 101 and back to a 100 when I sprayed it

#11

Control module temp is 103 and fluid is 100 right now

#12

That’s means the circulation is good right?

#13

I kept spraying and it won’t go below 100c for fluid temp and the control module is at 103

#14

Definitely when I was driving I saw the temp trying to drop a bit

#15

I cant really speak for the control module and its desired temps. But it sounds like a flow restriction to me. Wish I could of more help. IMO 103 degrees is not too hot, 270 degreesF I would assume problems. My shit is up and running and it is hot today I can check my trans temp.

You might try and log the trans and get it to throw code / limp and provide us more details. Also compare ECT sensor temp vs trans coolant & ATF temp

#16

When you say you were driving and temps dropped a bit. Which temp? ATF, Trans coolant, or ETC?

103degC is within range for coolant temp on these beasts. Desired is 93degC but the electric thermostat adjusts for mileage vs performance “so they say”

#17

The fluid temp went up to 112c and kept going and it’s not even really hot out it’s only 78 degrees. What I’m thinking of doing is removing the atf cooler and seeing if that thing is clogged

After that I’ll probably install a separate cooler for the thing and hopefully that works

#18

The atf fluid it steadily went from 112 to 111 when I was cruising a bit which I assume is the air hitting the aux radiator cooling it a bit

#19

It might be clogged yes esp if the trans fluid was old and burnt iirc you mentioned that. However the ETF cooler is pressurized so doubt clogged but possibly dirty. I would remove it and soak it in phosphoric acid “aluminum brightener/ concrete etcher” and itll be brand new

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#20

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