Automatic transmission fluid flow question

I'm hopefully doing the transmission cooler install myself soon and am looking to find out which line is the return and which is the supply. Based on the picture posted, which is which?

Also, can I use an infrared gun pointed at the pan? Has to be between 115-135 degrees as far as I know.

Thanks in advance

 

return is the lowest one coming out of the radiator
or
with a tranny cooler in front of the rad, the line
that goes from the tranny cooler to the tranny directly.

in your pic the top one is into the transmission


double check. follow the bottom oil line at the bottom of the radiator
to the tranny.

if you use FLIR obviously one line will show cooler on FLIR

 

Thanks for clarifying that more! I really do appreciate your response. Do you think it's safe to use an infrared gun? I just don't want to spend 150 bucks on a scangauge to use once or twice

 

no it is safe to crawl under there and follow the line from the from the radiator
to the tranny to be 100% sure which line is which.

infrared gun will not be accurate enough to measure anything meaningful
outside the transmission. you need to get the reading from the actual temperature
sensors inside the unit to know what temp it is.

safe to use a gun, sure. but won't give readings that make sense on how
you operate the tranny. flir would be more accurate but if you are not keen
on spending on a scangauge I reckon the cost of flir would be too high

if you want to know which line is which, it is always the bottom line on the
radiator is the cool line going back to tranny. Most trannies, it is the top line
on the tranny but not always.

if you want to know tranny temps, you need to poll the canbus for that data if you want accuracy

transmission temps rise and fall rapidly. if you were able to externally measure temp, it would be far different when you stop, jump out, and measure something...the temp will fall fast. if you watch a real-time tranny temp monitor
you see how fast it rises and falls depending on what the vehicle is up to. you jump out and take a reading, it's gonna be lower than what is happening on the highway.

 

Duly noted. Looks like I'm buying a scangauge.

 

Good info.

 

Is it weird that I expected to see a photo of transmission fluid leaking onto somebody's driveway when I opened this thread?

 

I'm really glad that wasn't my problem

 

Post Traumatic TurdGen Disorder

 

Sorry to hear man. Crossing my fingers that doesn't happen to me any time soon. Changing gasket sucks.

 

Can't you build a little jumper to plug into the OBD port to turn on the transmission diagnostic mode that will tell you with blinking lights when the transmission fluid is at the right temperature?

I know it was possible in earlier generations. It seem like a few inches of wire would be a better investment than a scangauge unless you plan on needing one for other reasons.

 

I would love to do that instead! Anyone know if this is possible?

 

You might try wading through some of the transmission fluid level check threads on here. I think there's a walk through. Then again, I am active in the 4Runner forum too so it could have been there that I saw it.

 

I think I found it but not sure if I wanna short out something that I am not sure about will work or blow a fuse (best case scenario). Anyone know if this works on 2016?

https://www.tacomaworld.com/threads/how-to-drain-refill-automatic-transmission.63851/

 

It's not risky, it just sounds like it is. I know it's been the preferred method for 4Runners since the 2005 model year (that's when the dipstick went away).

But I'd still find someone that's done it on a 3rd gen and talk to them before doing it.

 

Knock yourself out t3mpo.
I've taken a paper clip and stretched it out and just bend it the adl terminals faster than techcstream if you ask me.

Hope that helps
Cheers!

 

Well hell... I will try it then

 

If that''s your fetish, look in some oil change threads.

 

Be very careful though, Toyota is very particular about their A/T, it might be safer to contact a dealer to see about their installation just so you can maintain the warranty.

 

I just tried the jumper and I do get the lights flashing but nothing really changes when I go from n to d six times then to p. Everything just flashes