DJK-West

I was driving home last night from Hollywood (about a 16 mile drive). Driving condition was normal, I had the cruise control set at 70mph. No steep uphills, mainly flat driving mixed with some incline but not much. I've been noticing this since I started driving my 4Runner daily again (2 months ago) that it constantly downshifts (rpm goes up to 4k) to maintain 70mph over slight inclines (only when cruise control is activated). I almost never go faster than that. Anyhow, last night the A/T Temp Light came on. It never did that before even when I drove past 70mph at one time or another. Anyhow, I had been driving for about 15 minutes, again normal driving conditions, maintaining speed at 70mph before this happened. I immediately exited the freeway, pulled over, put the tranny on P, and let the engine idle for 10 minutes. The operator's manual stated to let the engine idle until the A/T Temp Light goes off. However, I have been driving on E and didn't want to run out of fuel as the engine idles. So after sitting still idling for 10 minutes, I shut the engine off, checked the tranny fluid, and engine oil while I was at it. No burnt smell from the tranny fluid, ATF level is normal. One thing to note is that when I popped the hood open, some smoke came out from the engine compartment. I do have a minor engine leak coming from the oilpan, perhaps the motor oil could have travelled from there onto the exhaust manifolds. I looked under the truck and there were no other visible leaks aside from the obvious leak coming from the oilpan. So I pumped some gas and started the engine. No more A/T Temp Light, proceeded to drive home and it never came on again.

I know that the ATF is due for a change, I'm thinking of perhaps doing a flush. What do you guys think? Could the A/T Temp Light be indicating that the ATF is breaking down and needs change asap? Could the tranny clutch be slipping, which is probably why the tranny keeps downshifting just to maintain speed on cruise control? This never happens when I don't have cruise control activated. How can I check to see if the clutch is actually slipping? The RPM needle doesn't shoot up when accelerating, which is a usual sign of slipping tranny clutch. My left foot is usually light on the gas pedal and I let the engine get up to speed on its own time instead of mashing the gas pedal to get the tranny to downshift. What do you guys think? One last thing, what's the best tranny flush method? I have read of two different methods and from my recollection, the one method where it uses some type of an external pump to flush the fluid thru the tranny is not good since it could force debri inside the tranny thru vital parts and harming them.

mt_goat

Yes, under normal conditions that light doesn't come on until the ATF reaches over 300 degrees F (the FSM says something like 305 F). I'd consider the ATF damaged at that point, unless its a good synthetic ATF anyway.

My 3.0 auto always did that too when on cruise control, even when new and under warranty. The dealer said it was normal. I think it has more to do with the cruise control and ECU (which controls the shift points) than the tranny.

Here's a good link about flushing, but the bottom line is your choices may be limited by what's avalible at your local shops. All the shops around here just use a type machine that doesn't even have a pump, the pumping is done by your own tranny ATF pump as it circulates the ATF to the cooler (something its doing all the time anyway). http://www.gadgetonline.com/TransFlush.htm

mt_goat

How's your coolant temps BTW? Unless you have added an extra ATF cooler, the factory ATF cooler uses the radiator to cool the ATF. That means the coolant is what is cooling your ATF. If your coolant in the radiator is 240 degrees F due to a cooling system problem the coolest the ATF can get is 240 F.

DJK-West

Coolant temp was normal at the time of incident. My 4Runner is a 95 limited edition with a tow package. I'm not sure if they come with special tranny coolers or still use the radiator for cooling. I looked behind the front bumper briefly today and did not see a tranny cooler normally found on newer trucks/suv's with a tow package. I took it to a reputable tranny shop today. They tried pulling codes from the TCU, no codes. They test drove it and they said the tranny shifted fine. The tech thinks it could be the temp sensor but he will verify that when they get under the truck. The tech did verify with me that the fluid is burnt up. He wants to drop the pan and see what they find. They are not recommending a flush since the transmission could be on its way out and the only thing holding it together is the old fluid inside. But they will see once the pan is dropped. Since they didn't have the time to do it today, I scheduled an appt for mid-next week, they're completely booked til then. I'm just going to be very light on the tranny, not that I was stomping on it to begin with. I drove it from Reseda to Burbank, around 15 miles, no A/T Temp light. So I guess I'm ok for now.

wiseguymmiv

My 95 4Runner did the exact same thing. On very slight highway inclines, the tranny would downshift to maintain my speed and occasionally cause the A/T Temp light to come on. I once towed an empty 5X8 enclosed Uhaul trailer 30 miles over moderate highway hills and the light came on then too. The next day, I took it to Toyota to pull a code, and they couldn't find anything. The tech said I'd have to cause the light to come on again and, while the light was on, pull the code.

Instead, I bought a Hayden tranny cooler online ($50-$70 as I recall) and had it installed. That was 3 and a half years ago, and I've never seen that light come on again. That's my rec. for your 95.

DJK-West

Thanks. I am already considering that option. I'm going to have the tranny fluid drained and replaced with a fresh one. Then install a dedicated tranny cooler.

DJK-West

Just an update....

Had the tranny serviced. This included the fluid drain and fill. They dropped the pan and replaced the filter. She drives a lot better now. I'll have them install a tranny cooler in a few weeks.

Luvmeye22re

Wow my heart was racing, then with the last post a feeling of relief. My trans was doing the same thing (my fluid looks old, lot's of miles, truck overheated etc.) I'm about to get a newer motor in it and just hope the auto trans lives until I can afford a 5 spd swap. Glad to hear it turned out ok

postaL

What did the shop charge you for the fluid drain & fill?

Today i was towing a 6x12 enclosed trailer that was moderately full (helping the gf move), and this A/T OIL TEMP light came on for the first time. By the time i reached my destination (10 miles after i noticed it), i shut the car off and it went away when i turned it back on.

Come back home, It did it again w/ an empty trailer.

Got to the destination, engine off, key out, key in, engine on, no light.

Dropped the trailer, and it hasn't been back on since.

Looks like i'll need to have the fluid swapped, so shoot me over that price and i'll appreciate it more than you know

mt_goat

DIY: http://home.centurytel.net/stevenjac...sh/tranny.html