this_marine

I have a 91 4runner, 3.0, A/T...I will give some back story, I have an awesome trail new my house, about 18 miles there and back and I ran it flawlessly and the next day I drove to work and I experience my first fan exploding fan, took out the fan bracket, battery, radiator, radiator hoses...I changed them all with stock replacements...about 3 weeks later I'm on the same trail and about 4 miles up my A/T temp light comes on...I found a nice spot to park it to let it cool down, finished the rest of the trail with no problems. I went home and thought about it and figured I was low on ATF. Added a qt, 2 weeks later on the same trail and my A/T temp light comes on again, parked it let it cool down, light came off finished the trail and no problems?? I don't get it when I checked the fluid level it was at the hot mark, I was thinking maybe it's the radiator? I read maybe I should move the trans cooler to a better spot? IDK what do you guys think? Thanks

Co_94_PU

iTrader: (-1)

Is it a muddy trail, have you crawled under and hosed off the aux cooler. Pretty sure the 2nd gens still have one..

this_marine

ya it did go through some mud awhile back, ill have to crawl under there and check it out
thanks

scope103

My AT temp light has come on only twice: once climbing a twisty hill in 4wd in Dinosaur Nat'l Monument, and once in sub-freezing weather at highway speed climbing a 4% grade.

The aux cooler is obviously there for a reason, so check that first. But what I think happened to me was spending too much time out of lock-up. At highway speeds, the transmission spends most of its time in lockup. But I was on cruise control, so the transmission kept shifting from OD to third and back -- spending much more time than usual out of lock-up. Which meant I was beating the ATF to death in the torque converter, and got the temp high enough to trigger the light.

Next time you try that trail, see if you can find a speed where you are in lockup, in any gear, rather than using the torque converter out of lockup. I think that worked for me.

warnereg

If its an A/T it could be clogged cooler lines, clogged filter, bad (burned) fluid (fluid should be red, if its brownish or clear its no good), TCC solenoid (heck, whos to say that the torque converter is actually locking), or it could be a weak, failing, or bad pump. My logic says its an obstruction of trans fluid flow. One way to check the flow if you dont mind making a little mess would be to run the vehicle and undo the inlet, and check flow, reconnect and then check the outlet of the trans cooler lines and see if fluid goes shooting out with a little pressure. Ive done this on an overfilled trans instead of dropping the pan or sucking it out through the dipstick tube. Do it cold so you dont get burned by hot fluid.

this_marine

Ok cool tomorrow I will clean it all up, find the aux cooler and make sure its all clean. Could I have burned trans fluid the first time it overheated? I had to drive it a good 15 minutes before I was safe to stop, and I think disconnecting the lines and checking for flow is a good idea as well. Thanks everyone!