1990 FJ62// A.T. Temperature Light On (1 Viewer)

[JCKruiser]

Anyone have any experience with a lingering A.T. Temperature light? Fluid level is good, then ran the truck for 30 minutes locally on some back roads and used an IR gun to check the temperature of the transmission pan and transmission below/above the pan. Everything was below 190 Fahrenheit after the trip. Not too sure if this could be a sensor issue? I did pop a new Optima battery in before I pulled out of the garage. It also triggered some faults related to the charging systems BRAKE/ENGINE lights. Maybe these are all related to a similar electrical fault?

I had the truck in the garage for about 6 months without any operation. The truck does have the common hard shift into R and D gears.

Is it due for a rebuild at 223k and this light is indicating some sort of internal failure/wear?

I'd like to get some opinions on this before we go higher order than necessary. But, at the same time, I don't want to turn a weekend trip into a s***-festival on the side of road in BFE... thoughts???

 

[Tiamat]

I would be suspicious of the light if your pan temp is around the 190 range with an IR gun. To give you some perspective, I installed a surface sensor for both the engine on the top half of the thermostat and a transmission pan bolt over a year ago. Normal temperature of my A/T pan surface sensor is around the same as the engine (180/190). The highest I’ve seen it go is dead heat of SoCal summer around 230 in stop and go traffic. I expect the internal fluid temp to have about a 10 to 20 degree higher differential. This is with no transmission cooler.

If that light really did come on the fluid would look pretty bad. you could open the pan real quick and catch a quart or two, check the color and proceed from there. Or just drain and fill since you’re already halfway there.