GX460 Transmission fluid cooler

[JCliftonB]

Lots of information in this thread:

OEM AT #Cooler Install - #transmission - ClubLexus - Lexus Forum Discussion

GX - 2nd Gen (2010-2023) - OEM AT #Cooler Install - #transmission - EDIT: This is more than likely the same setup going into the 2020+ GX 460 with off-road package. This has also long been available since 2010 in Canadian high trim models. As of 2019 this cooler is part of the Executive Package...

www.clublexus.com

Thank you!

 

[taco47001]

Another successful and stress free install thanks almost entirely to this thread. Thank YOU!

 

[Acrad]

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

 

[alefer5]

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

 

[myunrealname]

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?

 

[ericm979]

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?

 

[Rednexus]

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.

 

[Acrad]

No... strawberry AT/Coolant mix on a 460 is ultra rare.

I have only heard of "one" incident in the last 5-6 years

 

[ericm979]

.

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.

 

[Acrad]

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.

 

[runnerxa]

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.

 

[suitcase]

Does anyone know if this OEM AT cooler will fit a 2017 GX460 Premium? The parts site for Bell Lexus indicates that this cooler (part number 3291060171) does not fit the Premium trim, but will fit the Base trim. I looked at the area below the horns on the radiator and it seems like there's room for the cooler to bolt right on.

 

[BigSwede]

Does anyone know if this OEM AT cooler will fit a 2017 GX460 Premium? The parts site for Bell Lexus indicates that this cooler (part number 3291060171) does not fit the Premium trim, but will fit the Base trim. I looked at the area below the horns on the radiator and it seems like there's room for the cooler to bolt right on.

I don't know why it wouldn't. I put an eBay knockoff of the OEM cooler on my 2018 premium.

 

[MotorboatMcGoat]

Anyone have any insight into how much extra fluid is bad for the transmission? I've been considering the Hayden 697 w/internal bypass to address the cold weather issue of not getting up to temperature in freezing temps. Ecatalog - https://www.haydenauto.com/en/ecatalog?partdetail=697

Hayden tech said it activates at 150ºF, and ideally to orient it sideways, but had no measure of how much fluid it holds.

If it IS in freezing temps, and the trans isn't getting above that temp, then a good portion of the external cooler is closed off, meaning extra fluid will be in the pan? Anyone keen on transmissions, fluid levels, and fluid dynamics? I know if there's an excess that the fluid can become foamy and lose performance. I've never been told how much is too much. Does fluid stay in the lines at all times? Are there valves to keep the vehicle 'charged' so to speak with oil, for when you turn off and start the car again?

EDIT: Called two transmission shops, one said to just top it off a small amount, the other said I'd be fine filling the hoses and cooler, but that the small excess or small lack of fluid wouldn't make a difference, that the fluid would stay in the lines and wouldn't all drain to the pan. One Lexus service manager said all GX's came with oil coolers , I assured him mine did not. What can one trust these days?

 

[Rednexus]

For my 470, I installed the Hayden 678 and purposely didn't install the 679 due to concerns with the longevity of the bypass valve and wild swings in trans temp.

With the 678 it will definitely over-cool in cold weather. Below freezing the trans might stay at like 120F under light driving, which is too cold.

I addressed this by cutting a piece of 1/8" rubber matting that covers around 2/3 of the cooler. I install it around November/December and then remove it in March. This blocks airflow through the cooler, leaving the exposed portions of the cooler that are roughly equal to the OEM cooler size on a 470. The trans runs 150+ in the winter under light driving with this mod.

 

[ericm979]

If you install the cooler with the inlet and outlet facing up, fluid will stay in the cooler when it's in the cool bypass mode.

There are devices to prelube engines and keep oil pressure up while running. They're used for engine oil in production based race cars where the oil pickup may suck air during hard cornering. I have never heard of one being used in a transmission though I'm sure someone somewhere has done it.

I'd just install it, add some fluid and set the level per factory method. Fluid volume varies quite a bit with temperature anyhow- warm fluid expands.

How are you plumbing the cooler in? Doesn't the stock system already have a thermostat, or is that just the factory cooler? There is one, it's just not installed on USA models except maybe in the last few years.

 

[jonshonda]

Well we towed with our 2017 Luxury this wknd and I will be adding the Hayden 679. I towed a lot with our 07 GX470 and heavily monitored the trans temps. While the OEM cooler did ok, the Hayden 679 I replaced the OEM cooler with sure did a much better job then the OEM cooler keeping temps in check. Yeah on some hilly and twisty roads where generous amounts of skinny pedal were needed not to piss off the locals, the temps would climb a bit. But RARELY over 200, and if so for a very short amount of time.

This wknd I was pretty light on the way home (firewood burned, food ate, beer drank, etc) and was seeing consistent temps in around 215-230* which is too much imho. And for the cold weather peeps, I do run grill blocks in the winter (on all my vehicles) and trans temps were happy in the 150's even on cold days.

Also note for people seeing above 200* just cruising around. Toyota transmissions are VERY sensitive to fluid levels. Being even just a little low will cause some high temps. I proved this after replacing the radiator in my GX470 (prior to Hayden 679 install, so still on OEM cooler). I was super pissed that the new radiator was producing temps 20-30* higher then the oem radiator, and was ready to just buy OEM toyota cuz I thought the aftermarket was junk. Well, after adding some fluid and confirming the correct level, the temps were reduced to the original levels prior to the radiator replacement. It was less then 1/4 qt low if I remember correctly, that's all it took.

 

[Roody]

Question for those who have towed distances with their GX in the past...

Next month I’ll be towing around 2,500 pounds on a ~1,000 mile round-trip adventure. Mostly highway, but some hills and some backroads with elevation involved. After the conversations we’ve had in this thread, I’m left wondering whether I will be fine or if I should scramble to get the parts for and install a trans cooler between now and then. I'm at just shy of 33,500 miles on the GX. Thoughts?

 

[Rednexus]

I'd just watch the trans temps via Torque Pro or another OBDII based app and be prepared to stop/slow down if things get hot (for me, 220F is when I've started to get a bit nervous, as some charts indicate fluid degradation above that). Then, when you have time, add the cooler.

If you are driving in conditions where the TC can remain locked (not sure which gears the 6-speed locks up at, but the 5-speed is 4th and 5th only), you really shouldn't have a problem. It's those times when it needs to remain unlocked for more than a couple of minutes when the trans temp can start shooting up quickly. On our hills here in MO I can usually manage without using my lockup switch, but my temp did crest 200F on a few really steep hills this past weekend, pulling 4K of our camper and gear, when I wasn't using it (grade was uneven so I left it unlocked to accommodate 3-2 downshifts).

 

[Roody]

I'd just watch the trans temps via Torque Pro or another OBDII based app and be prepared to stop/slow down if things get hot (for me, 220F is when I've started to get a bit nervous, as some charts indicate fluid degradation above that). Then, when you have time, add the cooler.

If you are driving in conditions where the TC can remain locked (not sure which gears the 6-speed locks up at, but the 5-speed is 4th and 5th only), you really shouldn't have a problem. It's those times when it needs to remain unlocked for more than a couple of minutes when the trans temp can start shooting up quickly. On our hills here in MO I can usually manage without using my lockup switch, but my temp did crest 200F on a few really steep hills this past weekend, pulling 4K of our camper and gear, when I wasn't using it (grade was uneven so I left it unlocked to accommodate 3-2 downshifts).

That's great info, thank you. Can you post a link to the Torque Pro kit you're using if you are so for iPhone? Guessing the "best" option for watching temps would be something like the ScanGauge, but that's not particularly cheap.