What can cause ATC light to come on and possible repair? Toyota 4Runner.
headgasket
Member Posts: 5
Have 1995 Toyota 4Runner 4x4 SR5 V6 Auto 220k mileage. I live in Colorado at Altitude.
Prolonged hwy speed ,pull up hill even slight grade after 20 minutes, hot or cold, loaded or not (slightly worse hot) ATC light comes on. If I continue to drive the performance drops and if I continue worst case scenario is trans fluid blows out of overflow vent. No other mil and all other gauges in normal range i.e. temp and oil pressure. I do not tow afraid to. Have to pull off road and wait about 5-10 minutes in order to continue. That sometimes is a problem since I am single female.
Recent repairs are battery, timing belt/water pump, cat back exhaust, tranny cooler flush and transmission fluid change. Mechanic says the trans fluid was not burned and had normal sediment for mileage. No change in symptom except seems more responsive after exhaust work. I can't say much for performance of this vehicle it is a slug.
Transmission shop of course wants to sell me a rebuild they don't want to address the symptom they just see the mileage and say replace or rebuild. IMHO that would exceed value of the vehicle and I still have 220k on engine so.....
Any suggestions to address the ATC problem any way to diagnosis what is actually happening? Larger trans cooler? Radiator has been flushed but not sure of the tranny cooler embedded in the radiator can be flushed. No coolant or transmission leaks.
Please help this is my only vehicle and need to get to work so daily driver as well. Hopefully can resolve since I would like to take it hunting this year early November but I have to drive 200 miles to get to hunt area it would take me day and a half.
Thank you
Best Answers
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Mr_Shiftright
Member Posts: 64,481
This is a known issue with your truck. I would say an external transmission oil cooler is the only sensible solution, and also, be sure to use the correct A/T fluid. Some technicians recommend changing from Dextron III to Dextron II.
Also make sure the transmission isn't overfilled.
The factory recommendation is Toyota Genuine ATF Type WS (ATF JWS3324 or NWS9638)
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Mr_Shiftright
Member Posts: 64,481
The problem as I read about it was that the transmissions overheat under any kind of load---so you couple that with age and lots of miles, and there you go.
I haven't seen your cooler---the type or even how it is installed. I have seen quite a few trans coolers installed incorrectly----either too much out of the air flow by being tucked into some frame member, or mounted horizontally an flush to the floor pans with no air space.
In any event, if you don't correct this, your transmission really will be toast.
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Mr_Shiftright
Member Posts: 64,481
Only if you don't trust your radiator; otherwise both coolers are better than just a stand alone aftermarket cooler. The ideal solution would be a new radiator AND an auxiliary cooler that is properly installed. (that is, in the air stream, and "after" the radiator).
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Answers
It already has an external trans cooler should I get a larger one? Not sure what grade Dexron is in it but can drop down to Dexron II or Toyota tranny fluid. The Toyotas are pretty finicky about their fluids I thought it was just a gimmick. Tranny does not register over full on dip stick. Thank you for the information where can I find that this is a common problem with my truck? Is the problem specifically geared to the ATC light/sensor?
Thank you, do you suggest transmission shop to check size and placement or a local mechanic?
Hello ?? Some of the other forums are saying to by-pass the cooler in the radiator and get the biggest tranny cooler I can get. Do you agree?
Thank you and have the work done by tranny shop or local mechanic?