crumble1013
New member
I have a 1991 4runner, V6 3VZ 4 wheel drive automatic, and last summer, on a hot day, it got low on coolant, making the engine temp go too high. I caught it soon, and added coolant, but later that day while i was driving on the freeway, the transmision shifted down into third gear for a while. Since then, as the weather has gotten colder, the problem happens more often. Now your lucky to get it into either lock up or overdrive. Replaced the thermostat, drained the radiator, replaced the temp sensor on the trans, and replace the trans filter and fluid. Replaced the engine temp sensor on the back of the engine by the firewall, and checked all of the wiring for corrosion from the ECU to the trans. Ever heard of anything like this before?
