A750F trans cooler upgrade

My very salty 2009/245k miles popped a pinhole in the trans cooler hard line and I can see another spot that's fixing to. A little JB weld got me patched up fine while I waited for parts.

I decided to go ahead and replumb it and put in a bigger cooler, since I'm gonna be all up in there anyway, and I may yet repurpose the factory cooler for the power steering loop.

Today's prep was fitting the fittings and the fire sleeve:


Here you can see the AN6 90 degree fittings and the trans housing to AN6 fitting adapters. (I replaced the clamps that came with these hose finishers with 100% stainless guys.):



3 feet of DEI fire sleeve starting from the tcase because of the proximity to the passenger cat:


Matching finishers where nobody will ever see them because fashion:


I have some AN6 (to fit the bare AN6) and some AN10 (which fit the fire sleeve perfectly) double hose clamps. Three of them will need to be drilled out and longer (stainless) M10 bolts purchased to put them where the factory brackets go.

The plan is to tear the face off the truck to do alternator, water pump, radiator (double row aluminum on order), and trans cooler loop all at once. I'll keep this thread posted with progress.

 

If you live in a cooler to cold climate, id probably recommend an inline thermostat to get trans fluid up to operating temp.

 

For the A750F tranny, what temperature will you be checking your fluid. 97-115 degrees or 115-130 degrees?

 

Post 14, 20, and 32.
I would say 105 is a good number.
Read post 32 as to why a little over full isn’t bad.
https://www.tacomaworld.com/threads/transmission-temps-while-filling-transmission.769913/

 

Are you talking about an in-line fan controller thermostat? I'm not putting a fan on - passive only, mounted in front of the engine radiator around the same place as the little factory trans cooler.

 

Im talking a fluid thermostat
https://derale.com/product-footer/fluid-coolers/thermostats-1/fluid-control-thermostats

You can actually cool your transmission fluid TOO much

 

Actually, that's a great call. This is the smallest Mishi cooler I could find (not wanting to exceed the OEM size by an astronomical amount) and I didn't consider what winter would do. Good looking out.

 

FYI, hayden makes a cooler with an internal "thermostat" bypass loop all in one plate and fin setup, i know you already have the cooler but if you are looking to go simple that would be the route.

 

The ATF cooler thread from the resident transmission guru.
https://www.tacomaworld.com/threads...l-toyotas-write-up-with-many-pictures.526283/

 

Hey @deanosaurus, got any info on the thread adapters you used here? I'm trying to figure out what thread size the inlet/outlet are off of the A750F transmission cooler lines. I'd like to do the same thing you have done here to my 4Runner.

 

They are either M14x1.5 or M16x1.5 - I don't recall which, but the fittings were not super expensive so maybe buy both to be sure? I remember buying the wrong one and then pulling the factory elbows and having to measure to order the right ones. Sorry. From the 6AN end I used a 6AN elbow to get them pointed toward the front of the truck and ran braided inside DEI fire sleeve where they go past the passenger cats.

There are some more gore shots of the install here and here:

https://www.tacomaworld.com/threads/new-england-b-s-thread.204874/page-9533#post-27726660

https://www.tacomaworld.com/threads/new-england-b-s-thread.204874/page-9533#post-27728296

https://www.tacomaworld.com/threads/new-england-b-s-thread.204874/page-9533#post-27732731

And I ditched the Mishi and went with a Hayden unit, a 696, and the magic inside it actually brings my temps up faster in the winter and keeps them in a pretty great range for the A750 (165-175 pan temp via ScanGaugeII) regardless of weather or load - VT winters/Southwest summers.

Edit: Based on eyeballing this picture, I would bet on the M14 fittings. It was 17mm to grab the factory elbow, and if the threads were 16mm they would look a lot closer in diameter.

 

Wow thanks for the quick reply!

 

https://www.tacomaworld.com/threads/transmission-cooler-upgrade.584900/#post-19488166

M14x1.5 into the transmission housing.