GX460 Transmission fluid cooler (2 Viewers)

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Lots of information in this thread:

Thank you!
 
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On a side note... if you you are doing a AT fluid drain and fill with this project or just maintenance on a 460 there is a built in temp monitor if you don't have Techstream, OBD Link/Fusion, Scangauge etc...

Your D indicator will tell you temp.. I like to know exact temp with TS and OBD Link but if you don't have any of these tools the built in should work for you. FSM says up until 2021 this still works... not sure on 2022.. perhaps someone with a TIS subscription can confirm.

D indicator will go off meaning below 115 degrees.. it will turn on at 115-126..the set temp... and then start blinking above 126 so overtemp for fill check

Remember OBD port is upside down from pic connecting pin 4 & 13


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Screen Shot 2022-05-29 at 1.06.53 PM.jpg
 
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los Angeles
On a side note... if you you are doing a AT fluid drain and fill with this project or just maintenance on a 460 there is a built in temp monitor if you don't have Techstream, OBD Link/Fusion, Scangauge etc...

Your D indicator will tell you temp.. I like to know exact temp with TS and OBD Link but if you don't have any of these tools the built in should work for you. FSM says up until 2021 this still works... not sure on 2022.. perhaps someone with a TIS subscription can confirm.

D indicator will go off meaning below 115 degrees.. it will turn on at 115-126..the set temp... and then start blinking above 126 so overtemp for fill check

Remember OBD port is upside down from pic connecting pin 4 & 13


View attachment 3020716View attachment 3020717
This is a nice video illustrating the process
 
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SLC
Not sure if this has been answered before but shouldn't we bypass the factory AT cooler built into the trans when adding an external air/air AT cooler? This would eliminate the likelihood of antifreeze mixing with AT fluid in case the radiator/built-in AT cooler develop a leak, and avoid costly engine repairs a la 3rd gen 4Runners. Thoughts?
 
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That's what I did when I had my VW Eurovan Weekender. The existing liquid cooler/warmer was known for both being much too small and for leaking. The trans was designed for a 2500 lb Passat but the EVWK weighed 4500. And dealers thought it was "sealed for life". They blew up a lot of transmissions.

Are the cooler/warmers in the GX known for leaking? I would expect them to be different from the 4runner since it's a different transmission.

The Lexus factory accessory air/air cooler comes with a bunch of lines and hoses that go all the way back to the thermostat valve on the transmission. Does the valve bypass the liquid cooler/warmer when it's open? Also, aftermarket coolers are simply plumbed in after the cooler in the radiator. What do the extra lines for the factory accessory cooler do?
 
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Bypassing the radiator completely might result in the transmission running too cold when it is cold outside and performing sluggish. Even with my small external cooler, I had to install a rubber cover for 3/4 of it to keep transmission temps above 120 when it was below freezing out (during light driving and not towing). Perhaps the 460 cooler has some internal thermostats that would help on this, but without any connection to the radiator, it might still run kind of cold.
 
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.

The Lexus factory accessory air/air cooler comes with a bunch of lines and hoses that go all the way back to the thermostat valve on the transmission. Does the valve bypass the liquid cooler/warmer when it's open? Also, aftermarket coolers are simply plumbed in after the cooler in the radiator. What do the extra lines for the factory accessory cooler do?

Turns out I missed the instructions to skip steps in the install document. The hoses and fittings in the clublexus thread go from the front of the rad to the back where they plumb into the existing cooler in the radiator.
 
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If one goes to the trouble of complete radiator bypass are they are pinning the AT thermostat open? I keep mine pinned open but if someone doesn't know what I am talking about... I would advise one to continue research.. all well published... so one knows how system works as fluid won't flow to the radiator until near 180-210 degree set point.. I've still not pinned down what temp it actually opens at.
 
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If one goes to the trouble of complete radiator bypass are they are pinning the AT thermostat open? I keep mine pinned open but if someone doesn't know what I am talking about... I would advise one to continue research.. all well published... so one knows how system works as fluid won't flow to the radiator until near 180-210 degree set point.. I've still not pinned down what temp it actually opens at.
I pinned the AT thermostat open on my LX570 and it keeps the transmission temp around 170 F during normal drives. I do have an aftermarket transmission cooler (Tru-Cool Max LPD47391) as well. The LC200/LX570 OEM transmission cooler (~double the size of the OEM GX470 transmission cooler) is retrofitted to my GX470.
If I live in colder areas, I probably would not pin it open all year.
 

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