Tranny Overheats on long drives....what now?

[4x4runner91]

91 4Runner SR5 4x4

I've been having a problem lately with my A/T Oil light coming on during long drives (45mins-1 hour or more). It never comes on in the city, only when I travel on the interstate for a period of time. I usually pull off an exit somewhere and let it cool down, then resume driving. I tested it on the way back home the other day and drove only 60mph all the way back....the light DID NOT come on. But if I exceed 65-70mph for a duration, it will most likely come on. The other day when the light came on, I noticed a strong "burning" smell that filled the truck, I assume it was the transmission. Just in the last several months this has been happening, and I've noticed that my transmission fluid, though full, has started turning brown. Im wondering if I might have a faulty/clogged TRANSMISSION COOLER? If anyone can give me any info or start me in the right direction of where to look, it would be greatly appreciated. Thanks

 

[SixxiA]

91 4Runner SR5 4x4

I've been having a problem lately with my A/T Oil light coming on during long drives (45mins-1 hour or more). It never comes on in the city, only when I travel on the interstate for a period of time. I usually pull off an exit somewhere and let it cool down, then resume driving. I tested it on the way back home the other day and drove only 60mph all the way back....the light DID NOT come on. But if I exceed 65-70mph for a duration, it will most likely come on. The other day when the light came on, I noticed a strong "burning" smell that filled the truck, I assume it was the transmission. Just in the last several months this has been happening, and I've noticed that my transmission fluid, though full, has started turning brown. Im wondering if I might have a faulty/clogged TRANSMISSION COOLER? If anyone can give me any info or start me in the right direction of where to look, it would be greatly appreciated. Thanks

My OEM cooler was hugely fouled with dirt and wouldn't really do anything in the way of cooling. It's not a large cooler, as it is, so I replaced mine with a B&M cooler, but I assume it would work if you pressure-washed the dirt out of the OEM one (provided that's your problem). I'd try this first and see if that's the problem.

 

[4x4runner91]

where is the tranny cooler located...and how exactly big/small is it? I've noticed a very small object under the passenger side of the truck that has fins much like a radiator....but its not bigger than a deck of cards...is that it? If not, what is that?

 

[SixxiA]

where is the tranny cooler located...and how exactly big/small is it? I've noticed a very small object under the passenger side of the truck that has fins much like a radiator....but its not bigger than a deck of cards...is that it? If not, what is that?

That's it! That little POS is the OEM tranny cooler.

 

[4x4runner91]

wow...thats so not impressive. So if washing it up doesn't solve the problem, I should just look to replace it with a new one? If so, what kinda should I get...(ie: I saw some that were pretty large, like an oil cooler, and some that were just a bit larger than the OEM one.) BTW...that a pretty dumb ass place to put the tranny cooler if anyone EVER thought to take the truck off-road...LOL

 

[SixxiA]

wow...thats so not impressive. So if washing it up doesn't solve the problem, I should just look to replace it with a new one? If so, what kinda should I get...(ie: I saw some that were pretty large, like an oil cooler, and some that were just a bit larger than the OEM one.) BTW...that a pretty dumb ass place to put the tranny cooler if anyone EVER thought to take the truck off-road...LOL

Haha, yup. Toyota kinda screwed everyone in the ass with the 3VZ-E and the transmission cooling system. I upgraded my cooler to a B&M cooler. http://www.autoanything.com/coolers/65A3046A0A0.aspx

 

[4x4runner91]

where would that particular cooler mount...near the radiator....or do you have to fab a place for it? Is there room near the radiator for it?

 

[SixxiA]

where would that particular cooler mount...near the radiator....or do you have to fab a place for it? Is there room near the radiator for it?

I have my engine pulled out, so I mounted it behind the Radiator and I'm prepared to make modifications to accommodate it, but provided you're not planning on a full overhaul anytime soon, I'd recommend mounting it in the same location. It should get plenty of air there, and plenty of dirt and debris, too. I got the large B&M cooler, but the medium sized one should work fine and mount in the space down there.