Hi all, I wanted to see if anyone knew which line was the return line and supply line for an 46RE transmission. I have the parts manual for the 2001 and it doesn't make sense. In parts manual it says, the back line is the "cooler pressure" and the front line is the "cooler return". Now these transmissions have a check valve in the what I would call the supply line that heads into the lower radiator but its conflicts with the parts manual so I am confused.

Here is the page from the manual, its a 46RE. I also drew in a diagram of how currently the 01 R/T Durango is setup with an OEM cooler.

Am I reading the information incorrectly? It would seem to me that the REAR is the return line and the front is the supply. The check valve prevents fluid from going back into the supply line when the car is shut off.

 

you are reading the diagram correctly, pressure line should be supply and return is return (duh), and yes there is a check valve in there (i believe its in the supply line), that picture runs the lines very close together (and dont show a seperate check valve), but it looks to me like the supply line is on the driver side of the radiator and the return on the passenger.

 

Yes the supply line should go into the radiator first, not the trans cooler. So the one that is directly connected to the radiator and the transmission is the supply line. Reason being, it wouldn't make sense to run through the cooler then back to the radiator where it will run through water that's almost 200°. It would just warm the transmission fluid back up before it returns to the transmission, not what you want to happen

 

Psp, that makes sense, but makes me wonder a bit more. Why pass the fluid through the rad at all? Wouldn't it be better to just have a separate trans cooler that was not susceptible to coolant temps?

 

Because the radiator warms up the trans fluid and gets it closer to operating temperature which is important in cold climates from what I have read. Most people barely warm up their cars.

I have also read that the 46re doesn't pump transmission fluid when it's parked, not sure how true that is.

 

I've always heard the same that fcastro said. In cold weather conditions I think it actually helps to keep the tranny fluid temp up, especially running down the highway when there's constantly air moving past the cooler but no thermostat controlling the fluid going through the cooler.

Some vehicles don't even have this set up. They have a "heat exchanger" that's supposed to keep the trans fluid similar to engine temp at ALL times. Some of them are before the engine thermostat so the trans fluid warms up quicker.

 

I think the diagram in the parts manual is simply wrong. Wouldn't be the first time.