my 97 PSD came with a small tranny cooler and not connected to the radiator. the 92 IDI that i swapped all the psd goodies into had the larger "towing package" tranny cooler, still not connected to the radiator. is there a reason that the cooling lines on both these trucks were not routed through the radiator? will i hurt anything if i use both coolers inline and/or connect to the radiator and use all three? or is it just better to use the larger cooler only? or...

 

One possible reason why they did not run it through the radiator is that if your tranny fluid is under the temp of the engine coolant, it would transfer the extra heat to the tranny fluid rather then cooling it down. It should not hurt anything to run the two tranny coolers in line. One thing that might not be a bad idea to get is a tranny temp gauge, it would give you an indication if you need more tranny cooler or not.

 

i thought the same thing about the coolant/tranny fluid temp. i do have a gauge, just havent swapped anything around yet. wanted to get opinions first.

 

Most likely the ATF doesn't go to the radiator because the previous owner thought that it would heat the ATF. That isn't true. The cooler in the radiator will ALWAYS cool the ATF. I have tested this extensively from +115 in Arizona to -40F near the arctic. The ATF is ALWAYS warmer than the coolant near the trans cooler.

The trans cooler is in the radiator on the return side. This is after the radiator has cooled the engine coolant. The coolant on that side is cooler than the engine temperature.

 

would it hurt or help (or maybe be overkill) to go through the radiator to cooler to bigger cooler back to tranny?

 

mine came from the factory ran throuh the rad.

Here's one to answer normal running my tranny temp is about 175* i have a 203*t-stat in my engine and my engine temps get to 190*so why would my eng. temp be more than the tranny and not almost the same

 

my queston is answered

 

One thing to remember is that the "cooled" fluid after the last cooler, needs to be piped into the rear trans line on the case. So you would come out of the front line into the radiator, then to the extra cooler, and finally back to the transmission through the rear line.

Coolers make a huge difference in the E4OD's life span. I'm getting ready to throw all the updates at mine for its second overhaul in 355,000 miles. It been running a cooler since about 100,000 miles. The first overhaul was at 150,000 due to a failed torque converter. This time its just getting a bit long in the tooth and showing some signs of slippage.

 

Because the transmission cooler is in the radiator on the cool side. The fluid that is around the trans cooler has already been cooled by the radiator. It is quite a bit cooler than engine temperature. If it were the same as engine temperature, why have a radiator?