Does anyone have a chart for the coolant flow direction on a 5.7?

My heater isn't working great. I know part of the problem is a bad servo for the floor heat on the driver's side but even when I manually set it for as hot as it can go the heat is sort of luke warm. Also it takes a long time before it gets warm. The temp gauge reaches normal operating range as it should but the heat still isn't great.

Looking at the plumbing the heater lines go to the heater core and then the transmission. The heat inside the truck seams to follow the transmission temp (when it's warmed up I get good heat). I would have thought that the flow would be to the heater in the cab and then to the transmission but now I'm wondering if it goes the other way and the thermo valve for the transmission is stuck open. I have the towing package so if it's open fluid will be going to the cooler in front of the radiator and then back.

I did replace the transmission fluid and manually opened the valve. It's possible I left it open or it might not be working. If someone has a chart so I can tell which way it's flowing I can either rule it out or dig deeper into it. My goal is not to pull the dash all apart.

 

Here you go. Note the ATF Warmer is in parallel with the line going directly from the Heater Core to the Thermostat. The 3D diagram does not include the ATF Warmer

Greg

 

Thanks. So the fluid should be flowing as I expected, through the heater core first and then down to the transmission. I didn't see any bypass at the transmission, just the two steel lines to rubber hoses to the round heat exchanger on the side of the transmission.

 

If you don't have the tow package ATF cooler and thermostat, the warmer is never by-passed. ATF flows continuously through the warmer, and engine coolant maintains the ATF temperature close to the coolant tempature, i.e. ~195 degrees.

 

I don't mean to hijack this thread but I feel like there is some good info in here. I have a 2014 Tundra with 129,000 miles. I went to plow the other day and noticed after being in it for a while that it wasn't getting warm. Temp gauge goes up to where I would expect it, replaced the thermostat thinking that could be the culprit. Blew out the heater core hoping to see it was plugged but it flushed out fine and seemed really clean. The weird thing is, feeling different coolant hoses that run throughout the engine bay, they all seem empty and not hot. I would think there would be some at least warm liquid in them. What am I missing. This coolant system has me at my wits end.