the problem started a couple of weeks ago. i was climbing a mountain pass (the second w/n one hour) loaded with camping gear, and all of a sudden my temperature gauge jumped from 50/50 straight up to max hot. so i pulled over, checked all hoses, belts, leaks etc... all seemed normal. i didnt want to chance it, so i had AAA tow me home. i did some reading, and i assumed it had to be the radiator/thermostat. so replaced radiator, thermostat with new hoses, fluid, and clamps. sure enough the lower half of my radiator was packed with mud, and wasnt running at full capacity. so, i thought the problem was fixed, until last night. again, climbing uphill the temp gauge rose up quickly, so i figured why not keep driving and see what happens. when the truck would go to change gear, it would hesitate then lurch heavily. then when i came to a stop the whole truck made a loud rumble sound (like i was driving on a washboard). i also noticed when ever i accelerated, my temperature gauge would rise. i continued home and parked it.

okay, now i am guessing my automatic transmission is overheating. so tonight i pulled the pan out, and changed the transmission fluid filter (see picture), which was filthy. the magnets were also stacked with microscopic metal shavings, so i wiped those guys down. i buttoned everything back together and topped off with new fluid. since its so late i havent had a chance to drive it yet, but i am praying it will fix the problem.

i wanted to know if anyone has experienced such a thing before? if so, what did you do to try to fix the problem?

my taco has 150,000 miles on an original transmission, and i am hoping i dont have to have it rebuilt.

 

Hmmm. Have no idea, but your fluid looks good and red!

 

That's not good.

???Why? Did your ATF too hot warning light come on? Sounds like to me you went in the wrong direction. Do you have any CEL? Have you ever replaced the water pump? Also check the fan clutch.

Since the ATF is cooled by the radiator your ATF might be getting too hot as a result of the coolant getting too hot, but generally the coolant doesn't get too hot because of the ATF getting too hot.

That's normal. The filter looks normal too from what little I can see of it. Won't hurt to change it and its always good to change the ATF after you over-heat but I doubt that fixed the over heating problem.

 

If you bought the truck used someone may have used a cheap trans fluid in it.A friend of mine had a t-100 that would throw a trans light each time he hooked a trailer to it. When he bought the truck it had bottles of wal-mart fluid in the bed. So he changed the fluid and filter using a good brand of fluid. It took care of the light coming on.

 

i agree i went in the wrong direction. but too, it never hurts to replace fluid. i never got a check engine, or trans overheat light. i am leaning toward some kind of electrical problem because when the problem happens, my tempgauge is in sync with my rpms. i dont know the first thing about testing electrical. i have an old multimeter from my science class.

 

What engine do you have? Year?

 

5vz-fe 1998. I havent checked in for a while. My computer was telling me that this site had been hijacked. Anyway, I took my Taco to a guy who tests electrical, and he found a ground wire melted to my exhaust manifold. This groundwire is part of the same circuit that controls my temperature gauge, and my fuel injection. So I had him swap it out with a new wire ($0.00 for the wire, $120.00 for the labor), and presto-chango, no more whacky temp gauge and lurching.