shift problems/trans oil overheat

i have a '90 4runner v6 w/ auto trans. in the mornings the trans seems to take a long time to hit o/d, also when i take a longer trip the trans oil overheat light comes on and it pukes trans oil out. any ideas whats happening?

by the way, the 4runner has almost 190,000 miles on it. it still runs strong except after driving on the highway for 20 or 30 miles when i slow down the oil pressure drops. thanks for any input

i have a '90 4runner v6 w/ auto trans. in the mornings the trans seems to take a long time to hit o/d, also when i take a longer trip the trans oil overheat light comes on and it pukes trans oil out. any ideas whats happening?

The transmission shift point is coolant-temperature controlled - sounds pretty normal. If you know the shift point has changed and is acting strange, consider replacing the engine thermostat.

Pukes transmission oil out of where on the tranmission? If you don't know where it's leaking, check the connections between the transmission and the cooler. One may be loose.

Your trans is suposed to delay the shift to o/d while the trans is cold. Your other problem, The trans overheat is a problem. The fluid that "pukes" out of the trans is from the fluid getting hot and expanding out the vent hole of the tranny. I have the same problem with mine and I am trying to figure it out. When I come up with the diagnosis I will post it.

My A/T Temp light comes on after i've been driving 70+ mph for a couple of hours on the interstate. I can pull off the road, turn off the engine for a couple of minutes and the light doesn't come on again. If you guys find anything out please reply back here.

Also, does the 94 4 runner have an external transmission cooler? Could it be that it's not working properly? I'm a noob when it comes to cars.

Thanks

Yes, the '94 4Runners have external transmission coolers. How long has it been since you've flushed your transmission?

Actually I bought the 4Runner about a year and a half ago and have not changed the fluid. The person I bought it from babied it so I would imagine the fluid was changed regularly.

And... I took it to a transmission shop this morning. They ran a diagnostic scan on it and it returned no codes. They checked the A/T fluid and said it needed to be changed but would also check the cooler flow. I'm taking it back in next week to have this done. I'll keep you guys posted.

Thanks

No problems with the transmission cooler flow... all they did was change the transmission fluid and put a new filter in. If I have the A/T Temp light coming on anymore I'll come back and post it. Good luck.

Good luck

i changed the fluid in mine, it seemed to fix the problem!

Good job

Well I went on a road trip this weekend and the A/T Temp light came back on... this is after I had the transmission fluid and filter changed.

The light came on heading to my destination. I was riding it pretty hard going between 70 and 75 mph (to see if the light would come on).
The next day when I was coming home... same trip, interstate, etc, the light did not come on... but I made sure to keep the rpm's below 3000 and drove between 65 and 70 mph.

Any ideas?

Thanks

Did your torque converter pretty much stay locked up at these speeds? It is supposed to be locked above 50 when cruising.

Sorry Brian, but that went right over my head. Can you translate that in to laymen's terms?

Thanks

The torque converter is a fluid coupling that ties the engine to the transmission. This is what provides the engine the ability to turn when the car is not moving. It is sort of the automatic transmission's equivalent to a clutch.

http://auto.howstuffworks.com/torque-converter.htm

Normally, when you are cruising up to 50, your torque converter is not locked. Above 50, it is locked and the engine is tied to the rear wheels, like with a manual transmission/clutch. The torque converter is what heats up your transmission fluid when it is not locked. There is a lot of energy lost in the torque converter. When it locks up, it no longer looses energy and the transmission/torque converter runs much cooler.

The reason I asked is that if your torque converter is not locking up at the speeds that cause your overtemp light to come on, then there is a possible reason for the overtemp. It should be locked up at those speeds. Once you get above 50 mph, it should stay locked up until you slow down below 45 mph or so.

Another reason I asked is that your rpms seem high to me for the speed you were driving. This is another sign that your torque converter was not locking up as it should.

If it locks up, the engine rpm will not vary with throttle position. If it is not locked up, then your engine rpms will vary alot with throttle position.

Thanks for the info... I'll see if I can put it to use with a mechanic...
Too bad your not in Arkansas

Thanks Brian!!!

You're welcome