Tranny cooler sufficient enough for AZ summer driving

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EvilMole

New member
The runner only has 114K on the clock, but at almost 20 years old, I figured it might be wise to bypass the radiator. I'm concerned that an external won't cool as efficiently as the radiator here in AZ. I'm assuming the radiator is original so maybe it's best to replace it and skip the bypass altogether. There's not much cost difference between a denso radiator and the cooler.

Any thoughts as what's best? Want to do this when I do the timing belt.
 
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EvilMole said:
The runner only has 114K on the clock, but at almost 20 years old, I figured it might be wise to bypass the radiator. I'm concerned that an external won't cool as efficiently as the radiator here in AZ. I'm assuming the radiator is original so maybe it's best to replace it and skip the bypass altogether. There's not much cost difference between a denso radiator and the cooler.

Any thoughts as what's best? Want to do this when I do the timing belt.
Click to expand...

I've had similar concerns. However, everything I've read or heard so far would indicate that the ext cooler alone is more than sufficient to cool the fluid. Also, the real reason for running it through both the radiator and the external cooler is to actually help warm it up quickly after start up in cold temps or colder climates.

So I think your ok down in Arizona.
 
I have been running just the standard B&M cooler the last few weeks in Texas. General driving it is okay but soon as I hit city traffic it has a hard time coming back under 195 degrees. I am already working to replace it with the larger B&M cooler for real summer temps and off roading.
 
Just make sure you install the cooler nice and snug against the AC condenser so that it has a good draw through from the Radiator Fan.

I know I'm up North, but we do get 100+ degree summer days here as well as bumper to bumper traffic. So far, my gauge has never read above 170F for the trans fluid.

Also, if your getting your temp readings from a ScanGauge II, those reading tend to be up to 10-20 degrees higher than you'd find on an Analog AutoMeter Gauge with electrical sender.

Can't tell you for sure which is more accurate, but I'm willing to bet that the reading from the Truck's computer is calibrated on the high-side. Just my opinion though, I have no facts to back this up.
 
tx_shooter said:
I have been running just the standard B&M cooler the last few weeks in Texas. General driving it is okay but soon as I hit city traffic it has a hard time coming back under 195 degrees. I am already working to replace it with the larger B&M cooler for real summer temps and off roading.
Click to expand...

what size?
 
tx_shooter said:
I have been running just the standard B&M cooler the last few weeks in Texas. General driving it is okay but soon as I hit city traffic it has a hard time coming back under 195 degrees. I am already working to replace it with the larger B&M cooler for real summer temps and off roading.
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Do you know what the temp was with just the radiator?

And, what willbgood said, or the model number.
 
I am currently running just the 70268 but plan to install the 70266 (w/ external thermostat) soon. I do not have any temps for just the radiator; sorry.

The smaller one is the B&M 70268.
The larger one is the B&M 70266.





My trans temp thermostat is inline within 4 inches of the fluid out pipe. The cooler works fine in the mornings; but soon as temps start getting above 90 degrees outside the cooler does not keep it below 180 at all. Once I get in town and the trans temp gets up to 200 it stays between 200 and 210 until I get back out of town. Remember - this is not summer driving! I live a little south of Ft Worth so we do have extreme temps so soon as I saw this I decided to upgrade to the larger cooler. I have about 1/2 to 3/4 inch between the trans cooler and the AC condenser on the advice of my friend who owns a radiator shop. It is close enough to draw a good amount of air when sitting still ( I can feel it pulling across my hand) and far enough away it does not act as a heat sink for the AC condenser.

Feel free to ask questions; I will answer them the best that I can.
 
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I am going with the bigger as well, with a fan, and thermos...southern Utah desert, and Arizona strip, heat to beat will have photos soon...My concern about to cool, will adjustable with the control.
 
Agreed; I have learned the hard way at work that when a hot object tries to cool itself with hot air it does not work. At that point the only way to help is volume of air. I will probably add a trans cooler fan later if needed. I know after driving these last few weeks with just the 70268 that anyone who is running just the 70268 had better stick to strictly street use. I wouldn't dare do mild to medium off roading with it. I doubt it would come back under 210 till the next day.
 
I'm here in phoenix too. I use this cooler: Hayden-Automotive-679-Rapid-Cool-Transmission

Temperatures measured at my remote filter on the hot side of the cooler range from 145 to 165 degrees in the summer. Or winter... it doesn't vary much.

I think the highest temp I've seen after installing this cooler is 195 degrees - that was low speed wheeling in 4HI. (good use of the torque converter)
 
turbodudey2 said:
I'm here in phoenix too. I use this cooler: Hayden-Automotive-679-Rapid-Cool-Transmission

Temperatures measured at my remote filter on the hot side of the cooler range from 145 to 165 degrees in the summer. Or winter... it doesn't vary much.

I think the highest temp I've seen after installing this cooler is 195 degrees - that was low speed wheeling in 4HI. (good use of the torque converter)
Click to expand...

I have tried to find out what the optimum temperature is, I would suppose it is the same for the engine cooling system, but I am not sure, and I can not seem to find the correct answer. I know the range for most engines, is usually quite narrow on both side of the scale.
 
Cogitating on temp gauges. Seems to me that if your temp gauge is attached to you cooler, you are only gauge the temp of the returning fluid, oi if on intake the temp of the fluid in contact with it.

This is not actually the trans temps, which could easily be much higher, especially if the there is a blockage, for whatever reason, in the trans cooling lines.

I think I am going to attach my gauge sending unit to the trans..
 
willbgood said:
Cogitating on temp gauges. Seems to me that if your temp gauge is attached to you cooler, you are only gauge the temp of the returning fluid, oi if on intake the temp of the fluid in contact with it.

This is not actually the trans temps, which could easily be much higher, especially if the there is a blockage, for whatever reason, in the trans cooling lines.

I think I am going to attach my gauge sending unit to the trans..
Click to expand...

I have duel inline senders hooked up. One is installed as close as I could get it to the trans send line and the other as close as I could get to the return line after the cooler.

In day to day driving, I typically see a 15 degree difference between the two with the send line never reading above 165F.

I don't know what the optimum operating temp is for the tranny, but since installing the cooler and gauge in the spring, I have never witness temps going over 165F.

I have not done any towing or wheeling yet though and aside from lift and 33" tires, I am not carrying any extra weight (stock bumpers, no gear).

Again though, I'm in Canada. The real test will be in the winter. A lot of people have been making me nervous saying that the trans fluid will remain too cool because I bypassed. I have a hard time believing this will affect me since I've never heard of a trans failure because of that, but we'll see.

The 70268 has a lowtemp bypass which should prevent this.
 
willbgood said:
Cogitating on temp gauges. Seems to me that if your temp gauge is attached to you cooler, you are only gauge the temp of the returning fluid, oi if on intake the temp of the fluid in contact with it.

This is not actually the trans temps, which could easily be much higher, especially if the there is a blockage, for whatever reason, in the trans cooling lines.

I think I am going to attach my gauge sending unit to the trans..
Click to expand...

Or you could use an app like Torque which if you have an '01 forward reads the ECUs trans temps so you can see what the 'puter sees. It changes rather quickly as hills come about and OD override are used. :cowboy:
 
jgue467 said:
The 'optimum' trans temp is the same as the engine temp given Toyo's design. :cowboy:
Click to expand...

Based upon what? the fact that the trans fluid is cooled by the radiator? Because if that is the design factor you are considering, it may or may not be true.

The trans cooler in the radiator does not necessarily cool or heat to the temp of the radiator simply because they have contact and built in the same condenser, (which is essentially what a radiator is). There are to many variables involved, such as the flow rate, flow distance within the condenser, and the cooling capacity of the fluids, just to name a few.

I would assume that the temps are close to each other, but I hate assuming, and I would really like to know. As of now, I am not sure.
 
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Worth noting that I do have the supercharger on my 4R. I have seen where some people say it makes a trans run a little hotter than if it did not have the supercharger. Beats me since I bought the 4R with it already on it.

YMMV.
 
SpidermanGeek said:
I have duel inline senders hooked up. One is installed as close as I could get it to the trans send line and the other as close as I could get to the return line after the cooler.

In day to day driving, I typically see a 15 degree difference between the two with the send line never reading above 165F.

I don't know what the optimum operating temp is for the tranny, but since installing the cooler and gauge in the spring, I have never witness temps going over 165F.

I have not done any towing or wheeling yet though and aside from lift and 33" tires, I am not carrying any extra weight (stock bumpers, no gear).

Again though, I'm in Canada. The real test will be in the winter. A lot of people have been making me nervous saying that the trans fluid will remain too cool because I bypassed. I have a hard time believing this will affect me since I've never heard of a trans failure because of that, but we'll see.

The 70268 has a lowtemp bypass which should prevent this.
Click to expand...

I like skiing and camping in the snow. and I live in the best part of this country for dying of heat stroke in the morning, and freezing to death at night. I literally sit on my porch, in shorts, for coffee in the morning, and then drive an hour or so, to ski, sometimes in sub zero temps.

If it runs to cold, you can do what us old guys have been doing for years on our farm trucks and diesel...either a heater, or a condenser glove. Simply design a glove that is adjustable with either Velcro, of zippers to place on the front condenser to adjust airflow to keep the temp optimum. I have also toyed with the idea of routing a hard line along the radiator to preheat the trans fluid. The problem is I cannot find a spec for the optimum temp.

I have toyed with a trans cooler cutout valve, and bypass system,(at the trans) for cold weather, but I worry that is reliant on an accurate gauge, electronic valve, and knowledge of the actual trans operating temp, which I am loath to locate. Also KISS comes into play, and must be considered, but I am not that worried, as we already have complex electronic controlled vehicles
 
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