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frnu · 06-16-2021, 11:37 AM

Hi. I have a 2003 Adventurer, 8.1 Vortec with a Allison 1000 5 speed transmission. Normally the fluid temperature stays around 140-160, but today it jumped all of a sudden to 240 degrees on the scangauge and the warning message on the dash says "check transmission temp" and a warning buzzer sounds. Driving on a flat road, no toad, ambient temp about 85 degrees. Fluid level is ok.
Has anyone experienced the same symptom? And what would be the solution? There is just no way that the trans temp could be that high.
Any help is appreciated.
Thanks
Fritz

Fred and Bonnie · 06-16-2021, 12:18 PM

Two possibilities come to mind. Following too close to a big rig truck, or trans cooler plugged or obstructed.

Fred

edgray · 06-16-2021, 12:20 PM

OR, the temperature sensor has malfunctioned.
IF nothing is obvious, you may have to visit an Allison dealer.

frnu · 06-17-2021, 06:00 AM

Would driving with a bad temp sensor messing up the transmission, knowing that it's not really overheated?

andy29847 · 06-17-2021, 06:56 AM

Radiator could be clogged up with bugs and dirt. Fan belt/fan clutch could be bad. Did you see any rise on the engine temps?

edgray · 06-17-2021, 08:49 AM

Quote:

Originally Posted by frnu

Would driving with a bad temp sensor messing up the transmission, knowing that it's not really overheated?

I am certainly NOT an expert on such, but I would think a faulty temp sensor IN the tranny would not affect the drivability. In fact, I don't KNOW if the data being sent to the OBD II port from the tranny gets relayed to the ECM, or not.

As others have stated, assuming you don't find any blockage of the cooling pack, and no indication of the engine temp being high, then the sensor itself would be the prime suspect. Has it remained high after a shutdown / cooling off period?

frnu · 06-17-2021, 04:04 PM

Thank you for your response. The engine temp is normal about 200 degrees. After 2 days of sitting in a park, by turning the key to on position, the scangauge still displays 253 degrees for the transmission fluid temperature. I disconnected the battery for about 10 minutes hoping it would solve the problem but it didn't. So, knowing that the transmission is not really running hot, I will continue our summer trip and hope the issue clears up on our next leg. if not, I will worry and address the issue when we're back home as long as I don't experience any acting up by the transmission.