CVT in Limp mode

[forger]

While driving on the freeway, I noticed my cvt transmission was slipping at speeds less than 60mph so I kept the speed at 65mph
to avoid the slippage. After a few more miles, my dashboard gear indicators lit up. After later researching, I learned
this meant the car was in limp mode. I was able to drive the car in this mode for about 40 to 50 miles. Unfortunately, when I stopped at
stop light, I could barely get the car moving at the lower speed. When I arrived home and parked the vehicle, the upper cvt cooler
line busted and leaked fluid. DCS tuning identifies the part as the radiator to hard cooler line(8E0317826T).

I have removed the upper cvt cooler line and will be ordering a new one. I would like to know what could cause the hose to bust before
I attempt to drive the vehicle with the new cooler line. My check engine light is on and the computer returns P0730 Gear Ratio Incorrect.
My vehicle is at 168k miles and I have never changed the cvt fluid. I was told my Audi customer service I don't need to change it. Does CVT
fluid wear out? I am thinking the fluid level may be low, but I have never observed any cvt fluid leaks till this episode.

I plan to replace the CVT fluid after I install the new cooler line to see if the worn out fluid or low fluid level is the issue.

[80sGuy]

CVT fluid should be replaced like all transmission fluids, usually suggested at 40,000 miles. It is also listed on the scheduled maintenance. There's an old myth about not messing with original (old) transmission fluids if they are high mileage but again at 168K what have you got to lose, I say it is the most reliable transmission for a CVT, unlike mine, replaced at 39,000. As for the line, it probably got old and worn out. Replacing it should be the remedy as it seem to be the root cause for your failure - as evidenced of the leak, but you have to make sure the fluids are at level again. At this point I think your best bet is to replace it because CVT is notoriously known for erratic behavior due to either under-filled or overfilling of fluids. It is not a simple task as there are many steps involved during servicing. Make sure you (or the tech) follow them accordingly when doing so.

[forger]

Thanks 80sGuy. I'm hoping there is no transmission damage. Some say it could be the TCM. When the cooler line arrives this week, I will have it towed to someone who knows how to drain and fill the cvt with new fluid.

[forger]

CVT fluid should be replaced like all transmission fluids, usually suggested at 40,000 miles. It is also listed on the scheduled maintenance. There's an old myth about not messing with original (old) transmission fluids if they are high mileage but again at 168K what have you got to lose, I say it is the most reliable transmission for a CVT, unlike mine, replaced at 39,000. As for the line, it probably got old and worn out. Replacing it should be the remedy as it seem to be the root cause for your failure - as evidenced of the leak, but you have to make sure the fluids are at level again. At this point I think your best bet is to replace it because CVT is notoriously known for erratic behavior due to either under-filled or overfilling of fluids. It is not a simple task as there are many steps involved during servicing. Make sure you (or the tech) follow them accordingly when doing so.

I followed the steps for replacing the CVT fluid ensuring I was at 42 degrees celcius when the fluid flowed out. Used the ODB11 to track temperature. The car is running like new, no more slippage. The gear shifting is smooth with no more noise. Unfortunately, when I attempted to do a live monitor while driving, the ODB11 would not connect. Getting message 'not authorized'. It worked yesterday? Anyway, thanks for your help and vote of confidence 80sGuy.

[80sGuy]

Cool. Everything looks to be in order. You did it yourself? Was it difficult?