pplusent

I have a 1993 4runner, Just rebuilt the engine, suspension, a/c, replaced differential bearings and wheel bearings,and the transmission and transfer case with new bearings, seals, friction plates, steals, torque converter and valve body including a shift kit.
Transmission runs great except for the temp. Kept getting the at over heat light after about an hour on the freeway, so I installed a 10000BTU cooler 30000GW after the radiator cooler. This did a good job until spring an then the heat came back.
Now outside temps are reaching temps over 100 degrees and soon will be at or above 110.
I installed a temp gauge on the cooler return line and the fluid is at 160 degrees when I first start the car for the day. Now I installed a B&M super cooler rated at 290200 BTU this cooler is doing a much better job until there is a traffic jam or I just get off the freeway, then the temps run at 180 to 200 degrees and remember the temp gauge is on the cooler return line not the output line. I have now changed over to synthetic fluid for the higher thermal breakdown ratings.
I am now wondering If I will be able to drive it when summer kicks in and the temps get over 110 degrees outside. Due to the size of the cooler it had to be mounted on top of the skid plate. I ran two 1/8 X1/2 steal straps from extra bolt holes under radiator brace and welded the other end to the suspension cross member. The cooler is on top of the straps and it's fan above that. cooler is mounted with break away straps in case of impact to the skid plate. The fins on the skid plate are bent down so they pull in fresh air and there is a 2 inch clearance between the plate and cooler. If temps get too bad I can take plate off for direct air flow, but I have to put it on for off road driving.
Does anyone have a similar issue and does any one have a solution other than converting to a manual trany?

pplusent

Also had drive-lines re-balanced and new u joints installed, and replaced both halve shafts,and rebuilt break system and two into one exhaust with out cross over and flanged cross section for easy tranny removal. Just sayin!

millball

Well, if the temp indication is 160' on cold startup, it is at least 70' out of calibration, on the high side.

In light of this, your 180-200' hot temps do not appear to be excessive at all, with actual temps likely to be substantially lower.

First thing I'd do is get some better instrumentation.

There is a fair likelyhood that if you are truly getting a hot tranny at highway speed, your torque converter is deficient, or not locking up.

Where did you source your new converter??

Yotard

Yep I have fought this battle for the past five years and even though the transmission is still working it has 170,000 miles on it and I know it can't keep getting 250+ degrees and survive that much longer so I bought a Marlin crawler manual transmission R150F and am ditching the auto. I put a Haynes cooler on it and it's fine on the highway but get it off road and won't stay cool no matter what I try.

pplusent

I believe the temp gauge to be correct, but it is a manual gauge and I think the long thermal-couple absorbs the heat from the day. It goes down to 130 as soon as it is started. The torque converter is of good quality and gets a 500 rpm drop,I get them from the same place as all the shops and I get them at Jober cost.

It now stays cool on the freeway, about 140 to 160, it's when I get off the freeway and come to a stop that the temps go high. The over temp light hasn't come on since the new cooler, but I am worried it will in the summer. It does also run hot when off road or in slow traffic jams. I have found in the city it runs cool as long as I keep it in lockup and catch all the light just right. It will lock up as low as 35 mph. I am just worried the summer temps are going to be a problem and I can always tell when it's hot because it gets sloppy and slippage increases, that's how I know the gauge is right. I would like to convert to a manual but don't have the funds to do it and I already have about 3500 in to it. Even If I sold it I could only get about 1500 for it being a salvage title.
Theirs got to be a way to keep them cool, I was considering a windshield wiper pump to mist the cooler when it gets hot, Or putting a cooler in the box with the AC evaporator since my evaporator temps run at 34 degrees I could spare a little of that air and still be comfortable..
I would swap it with an AW4 if I could find one, but the are few and far between.
If I come across the funds i would build a 4.3 Chevy stroker and do a Chevy drive train. but that's a dream at this point.

wyoming9

iTrader: (1)

Myself I would look at the fan set up you have .

While the cooler is able to remove the heat it can`t be removed fast enough .
Just how is the fan set up ??

Does it draw air through (up) or push the air (down)??

Then where is the air moved to in a slow speed when the vehicle does not generate enough air flow ??

The heat is not removed from the cooler because it is not moved away fast enough at slow speed .

Then add in the heat from the engine the heat from the ground it all factors into the over all cooling load

pplusent

It has a 12 inch fan mounted on top of cooler. there is a lot of air blowing down on the cooler from engine fan, so i set it up to blow it down through the cooler, but this caused higher temps so I reversed the fan to pull up thru the cooler from the ground. This flow seems to work much better. I think the skid plate is just to restrictive, but there is just no where else to mount it. I just need some way to route fresh ram air to it.

wyoming9

iTrader: (1)

In your slow moving drives off road or traffic what ever .

You don`t need more air you need to get rid of the hot air.

I feel your not understanding

I tried

pplusent

Due to the engine compartment design air only escapes right behind the skid plate. The temps here in the summer are 110 and above, the air temps off of the street are 150 plus with an engine compartment at 200 plus. There just isn't any cool air to be had. I think I will just have to do without the skid plate in the summer or do some kind of ducting to get ram air through it.

angrydogtattoo

My experience, these coolers are designed to be in front of the radiator, with fresh air blowing through them? Seems the setup is the issue...my $.02, I've never had my A340h hot, but I do not live in that type of climate, when I had my transmission rebuilt, bought the truck with it bad, PO hit the pump linkage off roading and burnt all forward bands, after I got it back from the shop (I pulled it and replaced it) I switched out the old radiator (contaminated with all the debris, cleaned the lines) with a nice after market aluminum radiator, runs cool, both engine and transmission...

pplusent

Unfortunately there is not enough room in front of the radiator. I did has the radiator re cored, but an aluminum one might help, i will look into that. Funny thing with where I live you don't see a lot of 4runners around in the summer other than the two wheel drive.

Yotard

Aluminum is not your answer. Copper is a 60% more effective conductor than aluminum. Your re-cored copper radiator is much better than any of the aluminum ones. You are right there just isn't enough room for a sufficient cooler on these trucks. The only place to put one is where the skid plate is and that is very vulnerable to damage. If your ac doesn't work you could use your condenser space for a flat plate cooler but that's about it.

I had really good luck running a Hayden 777 on the front fascia below the bumper and not running it through the radiator at all. It wouldn't get above 210 anymore. That all went away when I put a winch bumper on it. But that might be a solution for you if your front bumper is stock.

pplusent

I looked at putting it behind the bumper fascia, but this just seems too susceptible to damage. I have considered taking the radiator cooler out of the loop, but just don't know that it would help or hinder.
I also have been wondering how much the rear cooler for the transfer case has to do with it? A lot of the heat in these tranys is from the married transfer case and the cooler is always over looked. Being mine has been changed out and relocated to accommodate the exhaust system I really don't know how much of a part this plays in the overall heat of the trany.
My Tacoma 2wd has the same trany without the transfer case and it has never overheated. The 4x4 just seems to drag those rear clutch pack and then there is the high stall converters on these v6 tranys. I have run both the high stall and the 1500 stall, but both heated about the same.
I have been thinking about making a cowling to force fresh air into the engine compartment and over the cooler for ram air, but once again space is an issue.

pplusent

.
Finally took the 4runner on a road trip to California and Mexico, 168 miles each way.
return fluid temp ran at about 160 degrees to 180, but the tranny would overheat every 50 miles. What I did notice was the engine temp would go up right before the a/t temp light would come on. I am assuming the radiator can't keep up with cooling and is heating up to much, so I have now removed the radiator from the loop and it is running between 150 and 180 at 80 mph outside temp 120 degrees. Now at the lights it will heat up when idle it goes up to as much as
200. I am now considering putting a second cooler before the A/C evaporator box since the evaporator temp runs at 33 degree, so it should only loose about 10 degrees at the duct or so on the a/C output temp. Has any one tried this ? I would appreciate any input you could share.
thanks
Lynn

pplusent

I believe I have cured the over temp problem. I have removed the radiator cooler altogether. I then installed a 1in thick cooler in front of the condenser utilizing the a/c condenser fan to cool it, this cooler is 10000 BTU.
Next I installed a 29200 BTU cooler on top of the rock plate mounting it with nylon zip ties so the cooler will break away if hit, this cooler has a 12 fan mounted on it.
Then I took the old transfer case cooler (since a new trans case cooler was installed when new duel exhaust was installed). I then took the old cooler and removed the mounting plates and installed it in front of the a/c intake under the dash. Now this small cooler is the final stage cooler and gets its air from the cab.
This set up works very well. It now stays right at 130 degrees on the freeway towing or not. get off the freeway and get in stop and go traffic and it can go as high as 160 degrees but rapidly cools once it gets moving.
I have tested it on I-8 where going through the date land az area at 80 MPH with outside temps at 120 degrees+ the trany stays right at 140 degrees. I have tryed very hard to over heat it, but it just can't do it. Highest temp I can seem to get it is 150. If it runs too cool I can just turn off the 12 in fan and turn on the heater in the cab. problem solved!

ZUK

iTrader: (1)

Hi ppl-
You have discovered what most have not....that the radiator cooler is not really a tranny cooler, it's a heat exchanger.....it shares the heated 170 degree water at the bottom of the radiator with the whimpy little piece of tubing that the tranny fluid is running thru.


angrydog and wyoming9 hit the nail on the head.....the tranny cooler needs a good flow of air and it needs to be in front of the radiator.

The radiator must be bypassed and the cooler needs to be run in "stand alone mode" and mounted directly in front of the rad using the 4 tie-raps that are generally supplied. As such, it should be the biggest possible and probably the thinner one (3/4" thick) to fit easily in front of the radiator.

It sounds like you have your overheating under control though.....but if you want the absolute best cooling then, as mentioned above, that's how you do it. My temps are measured at the transmission OUTPUT(point of maximum tranny temp)....yours are on the return to the tranny(point of absolute MINIMUM tranny temps) so it is uncertain what your actual tranny output temps are.

Mine is the Hayden 679(see below) that measures roughly 11" x 11" x 3/4" thick and fits easily on the front of my radiator and behind my condensor. It pulls large amounts of air from the engine fan even when crawling on trails at 100 degrees. My tranny temps, as monitored by the scangauge2, are anywheres from 110 on the highway to 170 on Phoenix area trails in the hot hot summer day......never ever 190 or 200 degrees has ever been seen.
edit---Mine is a 2001 Tacoma 3.4L auto with a front SAS conversion and using a tiny radiator ...application is from a 2wd 22re pickup
see this post of my build to see the radiator and the mounting of the tranny cooler
https://www.yotatech.com/forums/f152...l#post52234256



By the way, your factory engine water temperature gauge is a joke....get some other means of monitoring engine temp. You have a dead zone from about 170 to almost 230 degrees where the needle will stay in the center without noticeably moving.....do you see how that could cause you grief? There is a false sense of security when you look at your eng temp gauge and it stays perfectly in the center no matter if you are stopped in traffic or climbing a long highway hill...makes you think you must have an amazing engine cooling system to stay so perfectly still with the gauge.

pplusent

Yeah the two biggest changes to cooling was the cooler in front of the radiator, but to Small at 10000 BTUs, the B&M 29200 BTU Cooler helped even more, but the tiny one on the AC intake inside the car was the biggest change.
I used to monitor the output but found it more important to monitor what the coolers were doing. So far I have gone from Phoenix to California, to Tucson 4 times and to our gold mine near Wickinburg 6 times, to lake Pleasant and Saguaro lake (towing a jet ski), all at outside temps from 110 to 120 and hasn't overheated once. In fact return temp never exceeded 140 degrees.
I think I got it.
Were is the cooler your mounting n the pick?

pplusent

Oh Never mind, I see it now that is the cooler in the radiator. Yeah they don't cool they heat. Mine will now use the heater inside the car to warn the fluid in the winter, much more efficient and safer.

Gevo

I fought this battle for many months. Eventually, after spendign a lot of time installing a cooler with a fan at the bottom, behind the skid plate, and it making nearly no difference.... I decided I had to take drastic measures. At about this time I had a tranny that was rebuilt at 216k miles and going bad again at 225. The heat was getting way to high, 260+ constantly.

After taking a hard look at the front grill, the new 3 core aluminum radiator didn't leave much room.

SOlution: I put spacers on the grill mounts and moved it out about an inch. Fit a new, smaller, radiator in the front and all is well now

pplusent

As for the cooler on top of the skid plate, it needs ram air to work, so I use thick weather seal around the cooler and bend down the ribs on the plate so they draw air in. Just saying for others who try it.
I will eventually find an AW4 tranny to put in and cure the problem. For now I Believe My 4th gear spag may be bad and is generating heat, but seems to be ok as long as I keep it cool.