| 'Transmission Overheating' Warning: Technical Questions | |
I've gotten this "Transmission Overheating" warning for several minutes on two separate road trips now. Both times have been at highway speeds (~75mph) under normal driving conditions.
Both times it has happened, I've quickly attached my GAP IID tool to log the the live temp. values (the tool shows values for "Transmission Control Module Temperature" and "Transmission Oil Temperature"). What I found is that the warning seems to appear when both temps reach close to 280ºF (~138ºC). Once temps reached around 285ºF (~142ºC) I would start to experience reduced transmission performance – very limited acceleration and rough shifting. After driving slower, the temps would eventually fall, and performance would snap back to normal.
On both occasions, after driving slow for 5-10 minutes, the temps eventually fell back in the 200ºF (~93ºC) to 220ºF (104ºC) range and stay there for the remainder of the trip no matter how I drove. On the most recent occurrence, I even tried to purposefully load the transmission with aggressive driving up a mountain grade, but the temps only increased to 223ºF after 15 minutes.
Tranmission Backstory:
- My transmission was entirely replaced under warranty in April 2021 due to a leak in the casing
- Two months after the replacement, I received the first 'transmission overheating' warning & returned it to the shop. They kept it for a week; inspected every square inch of the new transmission; and test drove it for nearly 30 miles and found no issues.
Technical Questions:
- Since the temp values seem to spike and then eventually return to normal and stay there, is there a chance this could just be a faulty temp sensor?
- The GAP tool reports two temps for transmission (Control Module and Trans. Oil Temp) – does that mean there's actually two different sensors or could both values be coming from the same sensor? The values correlated to each other within a degree or two, but they didn't change at the same time which seems like it might be two sensors.
2021 P525 | Eiger Gray
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26th Jul 2021 9:45am
