91 4runner A/T oil temp light, and temp. gauge

I have a 91 4runner v6 4wd, If I drive my car over 50 miles, my A/T oil temp light comes on and my temp gauge goes up. Its not exactly at 50 miles but around there. Does anyone have any ideas why? It is fine after it is turned off for a couple hours.

How is your gas mileage? If it is pretty bad, maybe you have a drag on your vehicle which is causing the AT to work harder than it ought to. Do you drive on really hilly terain? Is your radiator filled? Check the radiator at the radiator cap when the engine is cold. It should be topped.

When is the last time you checked your ATF level? Maybe you are low on fluid. Have you changed it in the last 100k miles?

If everything seems to be good, pull one of the hoses to the tranny cooler, hook another hose to the radiator nipple with both hoses in a receiver and then idle your engine. See if there is a reasonable flow of fluid through the radiator. You should get around a quart in 5 seconds if my memory serves.

See if your radiator is plugged internally (watch the flow with the cap off cold) or has a lot of debris blocking air flow through it. Does your radiator fan work correctly?

Check that you don't have a pinhole leak in your radiator by using a pressure test kit. If the cooling system can't maintain the ~15 psi pressure (I'm guessing, don't know your truck's actual spec), then the temp will eventually creep up due to the boiling off of water and coolant. Good luck!

If you have been in the mud check the AT oil cooler mounted on the frame on the passenger side near the front of the tranny. Just a thought, post us back when you find out. (this shouldn't affect the engine temp though...hmmmm)