1992 4Runner Auto. Is this normal?

1) I was going over the Sierras, California to Nevada, and found that the A/T temp light would come on if I ran it above 2500 RPMs. So I was was going about 45 mph the whole way.

2) I was going about 70 mph at about 3000 RPMs Seems a little high but I've never driven another 2nd gen 4Runner.

 

3000 at 70 sounds about right. Not sure about the auto though. My manual 3.0 runs 75 at 3500 RPMs with stock gears and 31" tires.

 

3K at 70 is normal for the older autos

 

I run about 3400 at 72 with 4.88s and 31" tires. My 3.0 absolutely gets best gas mileage when the motor is running 2700 to 3200 rpm on the highway. (20.59mpg a few nights ago) Also, I had trans temp light problems when lugging it too much. If I'm going up a long grade I switch off O/D and it'll never come on. Also had trans flushed at Toyota with the correct fluid in transmission (Dexron III I think) and the transfer case fluid also. Does not come on nearly as much anymore.

 

I've had the AT temp light come on about 3 times when I drive through the Sierra (ahem; Sierra is a collective noun meaning "range," you weren't driving through the "Sierras.") In my case, I've pulled over for about 10 minutes and that resolved it.

I drive on cruise control all the time, and I think I get to just the right grade where the transmission is shifting back and forth in such a way that it never reaches lock-up. The Torque converter is working away, raising the temperature. I suspect that if I took it off cruise and "hand drove" it to keep it from shifting as much, I wouldn't get the temperature issue.

But this is just a guess.

 

That's why it's best to have the O/D off as drewgarret suggested.

Stops the hunting, allows the torque converter to lock up which reduces the heat generated.