As you might expect, the A/T Temp light indicates that the A/T fluid coming out of your torque converter is too hot.
There are various reasons trans fluid might overheat:
-Towing a heavy thing up a long hill
-Old fluid overheats easier than new fluid
-Low fluid level, causing what little fluid there is to work too hard
-High fluid level, where the gears churn the fluid up and make it foamy, meaning it slips more inside the torque converter
Most of these things will only show overheating after a fair drive on the freeway or up a few hills.
-Failing, over-sensitive AT Fluid temperature sender- if the light comes on after just a few minutes driving, I'd look at this one first. It's only supposed to trigger when the fluid is at 140C, so if the light is on and the fluid is *really* overheating, the cooler pipes will sizzle if you get them wet. If they don't sizzle, the sensor is telling lies.
On the right side of the gearbox, look for the pipes that go to the oil cooler. Where the front pipe comes out of the gearbox there's a T-piece with a brass sensor screwed into it. Swap that out for a new one and see if your issues go away.
You seem a little unsure about whether your fluid level is fine or if it's too low. Get the gearbox nice and hot (a 20 minute drive should do it), shift the gear lever through each gear and back into park, leave the engine running, and check the fluid level on the dipstick. The fluid should be clear and red, not murky and brown, and should be between the "hot" marks. Don't trust the cold marks, they tell lies. Only check it when it's hot.
White Mule wrote:Possible low transmission oil cause?
The image you've linked to is for the manual transmission, so that might be what's a bit confusing
