01M Transmission Normal Operating Temperature

Hi,

I purchased a Bluetooth Code Reader off EBay, and enjoy all of the extra engine data that is on my smartphone, especially the transmission temperature.

I live in coastal Virginia, relatively flat, and it usually indicates around 230 degrees F in highway driving. Yesterday, I noticed the transmission running warmer than normal, going up to 256 degrees, as well as noticing the engine operating at higher RPMs than usual. I went into the diagnostic mode while driving, and it had popped a P0740 code. Once reset, the RPMs went to normal and the temperature returned to the 230s range.

Is 230 degrees a normal operating temperature for this transmission? Would adding an external transmission cooler help preserve the transmission?

Seth Anderson
Moon, VA
2002 Jetta TDI Automatic 220K miles

Not that I'm well versed in 01M's, the literature I have for my 09A says max operating temp is 250*f....i run a scangauge with an xgauge for ATF temp, and the max I've seen was 80*c...normally hangs out in the 50-60* range. Southern ontario so a few good hills....i also tend to kick the cars ass when warmed up. Diesel torque is fun lol

I’m curious of the real answer of the proper ATF temperature range for these transmissions. And if the internal temp sensor on the trans is accurate

Very common for the temp sensor to fail, as I recall, and a pain to replace. Perhaps more 01M users (I'm not one, thankfully) that monitor it will chime in, but I thought from prior readings years past the tranny temp when operating properly, would be quite relative to engine coolant temps. The OEM cooler/heat exchanger being pretty efficient.

I’ve had a running theory based on only my own experience that the transmission operating temperature getting to high, from city driving, stop and go, sitting in traffic etc. is what sounds the death knell for the 01m.

I’m afraid I have no idea what the normal operating temperature should be, however a value close to the engine operating temperature seems reasonable.

Tdijarhead said:

I’ve had a running theory based on only my own experience that the transmission operating temperature getting to high, from city driving, stop and go, sitting in traffic etc. is what sounds the death knell for the 01m.

I’m afraid I have no idea what the normal operating temperature should be, however a value close to the engine operating temperature seems reasonable.

Click to expand...

I understand that overheating is pretty much the only reason an automatic transmission will fail. And of course, overheating is a broad term with many causes and consequences, but when the fluid stops being fluid-y then, it's not a fun time.

I was about 2.5 hours into a 100% highway trip, had not shifted out of 4th gear, or gone below 70mph in over 45 mins. VCDS told me my trans temp was 127-130C. I thought that was quite high.
"Wait a minute...100C = 212F...130 has gotta be like 260F!"
A calculator told me 130C = 266F. Eek.

seems awful hot for a trans that isn't doing any shifting, in 70F weather, moving at high speed.

Torque converter slippage would seem to be the cause of most high fluid temps. If the torque converter properly goes into lockup mode when it should there should be little excess heat produced. Heat is wasted energy.