Added second trans cooler silverado 5.3.

Ozlander wrote:
By spacing the cooler away from the radiator like you did, the fan can't suck air thru it. No cooling when you stop at lights.
The factory engineers know what they are doing.
Put it back like it was.

But yet you put your hand in front of the grille with the good closed you can feel the air getting pulled through!

By spacing the cooler away from the radiator like you did, the fan can't suck air thru it. No cooling when you stop at lights.
The factory engineers know what they are doing.
Put it back like it was.

You can certainly have trans fluid too cool. Why would they route the lines next to the exhaust manifolds if they didn't want it up to temp? They make trans fluid to work up to 250+ degrees. It does degrade faster at those temps, but I would run it at 200 all day long. I've tore apart e40Ds, 5r110s and 48res. Clutch slip from soft shifts and not enough line pressure ruins more trannies than heat. Plus fluid these days is made very "slippery" for the softest shifts because people are whiners. There are some superior fluid concoctions out there over the oem.

Im pretty technical savy and believe you cant overcool a transmission.

Its like giants vs jets...

Millions of transmissions running in the cold motor city area and artic regions .

Trans fluid flows @ -40 F AFAIK..

One thing I remember from automatic transmission class is overcooling can be just as dangerous as overheating the fluid in certain situations and one should always run a OTA cooler before the OTO so the radiator can warm the fluid back up. While not practical our instructors shop truck had three temp gauges to show how much of a difference there can be in oil temperatures Pan sensor, fluid Out and fluid In sensors.

Modern light duty trucks (yes, your ram 3500 is light duty) use thermostats to bypass the oil to air coolers until a certain fluid temperature has been met. One does not want to be towing in overdrive, 45 degree outside temperature and be cooling their trans below engine coolant temperature.

This is a good install. The number 1 enemy of transmissions during towing is heat and the coolers go a long way to preserving the transmission.

Something some people add is a thermostat that will bypass the aux cooler until until it's needed.

For me, my new to me 2008 F150 came with out the factory tow package. It has a standard Radiator and a standard transmission cooler. The radiator is about 1 inch thick and the HD radiator is about 1 1/4 thick but has more cooling fins per square inch. The transmission cooler is a four row cooler vs the HD cooler which is a 9 row unit.

I'm resolved to installing the bigger radiator when it's time for some heavier towing again but I'm not sure if I will install the factory 9 row transmission cooler or go with a two cooler system like you have.

Thanks for sharing your clean install, it makes me think more about what I want to do.

Thanks!

Jeremiah

Nice looking install. I'm not a big fan of adding additional trans coolers in general especially when the factory already has both the OTA and OTO coolers installed. These cooling systems have a lot of design in them and include a critical factor that adding an additional cooler to what is already there can have a potential negative impact. That factor is "flow rate". A specific cooling system has a flow rate window where if you happen to reduce that flow outside that window you can negatively impact the overall cooling capacity and effectiveness. IMO the most critical part of a good heavy duty trans cooling system is making sure that the OTO cooler is working at it's most effective point since that is often where cooling issues are the most critical and the OTA coolers do little to augment that part of the cooling equation.

Another thing many don't realize is that trannys are designed to operate at temps in the 170 deg or so range and getting them up in temp closer to 200 deg is actually beneficial since it helps keep any moisture in the ATF down thru evaporation. Thus adding too much OTA cooling can actually negate this benefit during cold weather and light load and higher speed operations where the tranny never sees much above 150 which is really not something you should want to see as a routine max temp.

Larry

Nice install. 140 was about what we ran after i put an aftermarket Hayden trans cooler on our 2007 Tahoe - towing out toy hauler fully loaded about 6k we ran at about 190 on hills and about 180s on the flat IIRC.

EXCELLENT JOB !!!!!

And able to keep the OEM routing back into the main coolant radiator...that keeps the ATF heated in extreme cold areas

Also, good job of documenting this nice mod