looking to add a transmission cooler to bypass the radiator cooler so which works better a plate and fin or a tube and fin with electric fan ?

 

I suggest you hook it up in series with the radiator cooler. A plate type is more efficient and I don't think you need a cooler with a fan unless you do a lot of off-roading especially in sand. Just my smelly opinions! LOL!

 

A plate type works much better than a fin and tube, but neither works as well as the radiator cooler.

 

When I drive in beach sand at speeds more than about 10mph, I start smelling transmission fluid. So, if I wanted to get aggressive on the beach sand, I would add another trans cooler with a fan in series with the radiator cooler.

My 05 Dodge Magnum Hemi which was built on a Mercedes platform and has a Mercedes drive train except for the engine has a separate air cooled trans cooler. I would prefer the radiator cooler. I don't know why Daimler Benz would choose that design.

 

As transmission fluid leaves the transmission at the cooling line, it is at the hottest point. As the fluid passes through the OEM cooling system, the temperature should go down. As the fluid returns from the the OEM cooling system, you should have cool fluid returning to the transmission in the return lines. This is where you want your auxiliary cooler. It will provide extra cooling if your transmission fluid is still hot, after passing the OEM system.

I have a B&M cooler with a built in fan. The thermostat switch is 180 degree Fahrenheit. I never saw the fan come on. You have to consider the fluid temperature. If the fluid temperature is still at, or over 180, after it passes the OEM cooling system; your transmission is in a lot of trouble. I modded the B&M cooler fan to turn on with a 140 degree Fahrenheit fin probe. The fan now turns on occasionally, in stop & go traffic, if my Scan Gauge II reads 210 - 220. Typically, airflow from the truck moving, and the radiator fan turning on, is enough to cool the fluid and the cooler fan does not turn on. Also factor in that a fin probe is not very accurate.

The B&M cooler is a plate & fin design. This is better than tube & fin, but not as good as stacked plate. With 20/20 hindsight, I should have bought the largest stacked plate design which will fit, and added an electric fan to it. Back when I was Jeeping, I used tube & fin coolers because they were inexpensive. Back in those days, the rumor going around was that stacked plate coolers tended to clog with particulate matter, which rendered a more effective design to be ineffective in real world use. But that was an old rumor, and stacked plates do work better than tube & fin. Adding almost any auxiliary cooler should provide for additional cooling. It's just as much effort involved to install a cheap cooler, as iis involved in installed a better cooler.

The more popular brands like B&M, DeRale, Hayden......all produce good products. Deciding factor may be cost. Spend as much as you want, for peace of mind.

 

The Radiator Trans cooler also helps to warm up the trans fluid on cold starts, so I think it is important to keep as part of the trans temp control system.

 

That is correct. The transmission won't even shift into overdrive till the fluid has warmed to a certain temperature.

 

No, it does not.

Have you ever measured this, or are you just guessing because the ATF goes into the radiator, which we all know is hot, right? Here is a revelation, NO, the radiator is NOT always hot! The ATF goes through the tank on the side of the radiator that has already been cooled. When the vehicle sits for hours and gets cold to the ambient temperature the radiator is outside air temp. When you start the engine the engine thermostat is closed so there is little to no heated coolant going to the radiator/ The cold side stays cold. It stays cold for a long, long time.

I've put thermocouples in the trans cooler lines, throughout the trans, and in the radiator. It was my job, for my last three years at Ford I developed transmission cooling systems. I looked for instances where the radiator cooler warmed the ATF. It never happened, I checked this in ambient temperatures from -40°F to +95°F and never found an instance where it was even close to warming the trans fluid. It does NOT happen.

Not correct, either. It won't lock the torque converter until the trans is warm, but it will shift to overdrive.

 

Thanks for the info, Mark!

 

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