GX460 Transmission fluid cooler

[Wildcat Walker]

I know the chart says above 240* F is not good, and the trucks warning system alert the driver at 260* ish F, then maybe my worries about hauling my boat (max load) are unfounded. I never received a warning or noticed anything unusual other than the slight warm smell in the first 10-20 miles of the trip when I hopped out to check the trailer hubs. That first leg of the journey I tried to stay in 4th and 5th to keep TC locked. After I smelled the warm smell I switched back to D the rest of the journey and kept it around 55 mph the rest of the trip. I went ahead and got a blackstone labs sample kit and will be sending a sample of the factory fill when I change it soon. I'm at 20k miles so its probably a good time for the first change, I may just do a drain and fill and clean the magnets next time.

 

[rav8]

Generally accepted ATF operating temps and transmission life expectancy. Many different charts out there from different sources but they all say the same thing at the end of the day.

Last weekend hit 228° in the torque converter briefly coming up the bluffs pulling 3K+ lbs. but sump never broke 198° where previously the sump would often also rise and equal TC temps and hold for quite some time. Really happy with the Hayden 698 and pinning the bypass for summer.

Some of those charts are based on old spec/tech. AAMCO, Jasper and TCI love to tell people that they need new components based on that guidance. What is good for a Slimjim, TH400 or 4L80E running Dexron/Mercon fluids is not necessarily good for modern Toyotas.

That said...neither myself nor anyone in my extended family going back two generations has ever had a transmission fail in any vehicle we have owned. I think it really comes down to careful maintenance and some luck.

Edited: Not to take away from your suggestions but the GX has built-in safeguards as @Acrad has mentioned. The vehicle will let you know before you are in really bad shape. Selecting the correct gear and speed for the load will almost always keep you out of trouble.

 

[Cold Iron]

Some of those charts are based on old spec/tech. AAMCO, Jasper and TCI love to tell people that they need new components based on that guidance. What is good for a Slimjim, TH400 or 4L80E running Dexron/Mercon fluids is not necessarily good for modern Toyotas.

That said...neither myself nor anyone in my extended family going back two generations has ever had a transmission fail in any vehicle we have owned. I think it really comes down to careful maintenance and some luck.

Edited: Not to take away from your suggestions but the GX has built-in safeguards as @Acrad has mentioned. The vehicle will let you know before you are in really bad shape. Selecting the correct gear and speed for the load will almost always keep you out of trouble.

I'm going with luck

Put 120K on early 90's Dodge Dakota and "only" went through 2 trannies. They were notorious for eating trannies as well as Dodge/Chrysler/Plymouth minivans back then. Got tired of the constant repair on the Dakota. Common saying on the Dakota board was at least they are easy to work on.

Had more than 100K on a Nissan truck without any issues back when they first came out right after they transitioned from Datsun to Nissan. No model number just Nissan truck. So I bought an Xterra my experiment with American vehicles was over. Found out about the SMOD Strawberry Milkshake of Death from leaking ATF and engine coolant so kept an eye on it. One day the overflow tank was pink so I traded it in on a new second gen Tacoma. 11 years no real issues.

FJ55 in the 70's and 80's no real problems, it had issues like all vehicles back then but it kept running. S10 did as well although paint peeled off it in sheets LOL.

Youngest son first vehicle 17-18 years ago was a second gen T4R with 130K on it. Owned and maintained by a lady at work that worked in maintenance. He got ~12K out of it before the transmission went.

Toyota has had some issues with transmissions over the years. Third (AKA Turd Gen) Tacoma's are a prime example. Friend has one with the typical TC shudder. Solution was to add a can of shudder fix

Never had to work on vehicle transmissions but did on ships main engine double-helical, locked train, articulated double reduction gear assembly's.

The hydrodynamic lubrication oil wedge prevents the teeth from actually contacting the other set of teeth. Bearings, turbines, pumps, heat exchanges, a lot of machinery crammed in a tiny space that I lived in at least 16-18 hours a day. The plant has a sound and feel to it much like a living being that you are always aware of. And can tell when things are good, or going bad.

For most of 20 years was someplace near the equator normally off the cost of some damn sandbox. But a few one off excursions to the Bering and Norwegian seas where air and water temps were 20-30 degrees cooler. The whole plant purred like a kitten in the cooler temps, most all machinery casualties were in the warmer temps.

You will often hear that heat kills transmissions for a reason. Which is why in the PXXX code fix thread one of the first things I picked up on was the geographic location of where most people lived that were having failures. Of course towing and stop and go traffic in some city will also do the same thing, generate heat. Someone on here only got 80K out of his GX on here before the tranny went, he lives in Arizona.

A Hayden cooler is a lot cheaper than a new tranny but you can have too much of a good thing. There are minimums that must be met as well which is why I went with a TStat Hayden. With the possibility of quite a few other issues it is all a roll of the dice in the end. We can try our best to minimize the chances of failure across the board, but in the end the roll of the dice have a bit to do with it as well.

 

[GXO]

I think I already added this, but if you have a GX460 and add a cooler, make sure you pin your transmission thermostat. It is under the truck and has a little button you push down and slide a pin into to hold the thermostat open. Why? Because it only opens at 200 degrees unless you pin it. That means no matter how much transmission fluid you have, it will sit there until it is 200 degrees before it will open and flow to the cooler....even if you add an aftermarket. So, pin your thermostat, add your coolers, and enjoy!

 

[Acrad]

I think mine has now been pinned for over 5 years straight. I did do a seasonal removal when I put my OEM cooler in back in 2019 but finally just left it in the following year.

 

[rav8]

With the possibility of quite a few other issues it is all a roll of the dice in the end. We can try our best to minimize the chances of failure across the board, but in the end the roll of the dice have a bit to do with it as well.

Those dice have been passed down generations last I checked from George Washington's stable hand. They're good!

I don't buy vehicles that have less than 6-7 years on them for myself. Wife gets all the new stuff. Gives me time to research what models/years have issues, My last 4Runner is nearing 300K after selling it two years ago at 220K. New owner loves it and takes good care of it. Toyota designs good stuff. I'm not going to try and outsmart them.

 

[GrizzlyClint]

My last 4Runner is nearing 300K after selling it two years ago at 220K. New owner loves it and takes good care of it.

Wow, 80k in ~2 years. That's a lot of driving.

I'm nearing 200k. The anticipation is real.

 

[rav8]

Wow, 80k in ~2 years. That's a lot of driving.

I'm nearing 200k. The anticipation is real.

He had just retired when I sold it to him so he has everywhere to go. We carpooled in it to multigun matches for years, so he was already attached to it. I imagine he is running it harder than I ever did, smiling all the way.

Edit: My GX is at 147k, just double the milage of what the original owner got while paying less than half for it. I have definitely got my money's worth. It should take me 8-10 years to reach 300k from here.

 

[Wildcat Walker]

Had my thermal degradation value read yesterday. 1011 at 20,800 miles. Maybe I didn't get the trans as hot as I thought. Went ahead and picked up a sixer of fluid at the stealership to do a drain and fill, $12/qt.

 

[GXFamily]

I can’t seem to find my parts list

Trying to help a friend install a Hayden 698 with a Goliath bracket.

There is not oem cooler installed so we are beginning with a fresh install. Which part numbers do we need to purchase for everything leading up to the core support where that metal tube penetrates through behind the headlight? From that point, we would connect the cooler.

 

[Wildcat Walker]

@Rogue556 Can you post a parts list for your cooler install please. cooler, brackets, etc. Thanks!

 

[theferg]

@GXFamily - if you hit the Club Lexus link that is posted at the beginning of this thread, it has a ton of info in the first post there. Descriptions and pictures of all the parts.

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

 

[thescreensavers]

I can’t seem to find my parts list

Trying to help a friend install a Hayden 698 with a Goliath bracket.

There is not oem cooler installed so we are beginning with a fresh install. Which part numbers do we need to purchase for everything leading up to the core support where that metal tube penetrates through behind the headlight? From that point, we would connect the cooler.

You don't need any special parts, it can be installed with the bracket and rubber hoses and hose clamps. If you want to buy something I think the hardlines that pass through the front is a nice addition but not required.

I would also recommend installing a Magnefine filter precooler.

 

[weejub]

I did mine two weeks ago.

Before, was running 200 degrees + in city traffic and have been like max 188 degrees since. It has gotten a lot cooler outside, but would expect to be 10 degrees cooler all the time, hopefully never hitting 200 again unless extreme load in the mountains.

I ended up only needing the two front hoses, the new shorty hose on the back, the pass through sub assembly, the factory cooler and brackets and clamps and bolts, and foam.

I used the bottom two longer existing hoses behind the radiator - the one that people are supposed to replace that has a bend, easily just bends up - it will probably fail on the trail or something, but looks just fine to me. It is like 1/2" too long, but rests nicely not really touching next to the radiator shroud if you just turn it.

Also save yourself some money and buy the front hoses from Toyota on discount - they carry them. Same part number fit just fine. I wish I would have "tested" this on other parts, but I think there are a lot of shared parts with the 4Runner - maybe all, maybe not the cooler or sub assembly.

The write-up on Club Lexus is amazing. Here is my list.

BTW Lexus wanted ~$90 each for these two hoses that I got on discount from Toyota:

 

[Rogue556]

@Rogue556 Can you post a parts list for your cooler install please. cooler, brackets, etc. Thanks!

I apologize for the late response. I actually just got around to getting most of it installed. I will drop a parts list here and the next few posts after will be the finished product (for now).

I actually was not able to install the Improved Racing Thermostatic Filter Mount as I had planned. I am still planning on going that route, but for now I am running dual magnefine filters before and after the cooler. I will hopefully have the Improved Racing Thermostatic Filter Mount figured out before this coming Spring, I just haven't had the chance to get to it, unfortunately.

We haven't had many hot days here in Oklahoma the past few weeks, so I am not 100% sure how well it works in hot weather, but so far the average drop in temperature with the thermostat on the transmission pinned has been between 40 degrees and 55 degrees F. First day I had it installed it was 60 degrees ambient temp. I drove with the transmission thermostat unpinned for 10 miles and saw temps of 188 degrees. I pinned the transmission thermostat and immediately drove the GX back to the shop that installed it to get as close to a perfect comparison as possible and saw transmission temps as low as 133 degrees. Yesterday with 75 to 78 degree ambient temps I had it at 145 degrees F on average. Highest I saw that day was 155 degrees F for a brief moment. Typically I'd have been closer to 190 degrees in the same conditions. During the summer I was seeing as high as 214 degrees just getting groceries with the family with ambient in the 90 degree to 95 degree F range.

Parts list below:

OE Tube Assembly 3290760290

OE Tube Bracket 3291360260

OE Bolt (x2) 9008011589

OE Transmission Cooler Hose 3294335050

OE Transmission Cooler Hose 3294335060

OE Hose Clamps (x12) 9046616004

Improved Racing MHX-521 Oil Cooler

Improved Racing MHX-150 Oil Cooler Mounting Bracket (x2)

Derale 59406 (7/8-14 UNF x 3/8 Barb 90 Degree) -10AN O-Ring Boss (x2)

Derale Transmission Cooler Hose 13017 (Manufactured by Continental. This hose matches the external diameter of the OE hose perfect, so OE hose clamps work as designed).

Wholesale Automatics GX460/Prado150 Single Cooler Bracket (Purchased with the complete cooler kit from Cruisers & Company)

McMaster Carr M8x1.25 16mm Button Head Screws 96660A231 (x25)

McMaster Carr M8x1.25 Distorted-Thread Flange Nut 3528N12 (x25)


Not Installed:

Improved Racing ENV-171-T2 165 Degree Remote Thermostatic Filter Mount (Not Installed)

Wix 51269 Hydraulic Filter 10 Micron (Not Installed)

Filter Mag FTM-MB300PR (Not Installed)

Derale 59406 (7/8-14 UNF x 3/8 Barb 90 Degree) -10AN O-Ring Boss (x4) (Not Installed)

Here are a few comparison pictures of the cooler that comes with the Wholesale Automatics GX460/Prado 150 Single Cooler Kit (Left) next to the Improved Racing MHX-521 Cooler (Right.

The (x2) Improved Racing MHX-150 mounting brackets, which I have mounted in reverse orientation, would not align with the Wholesale Automatics bracket, so I made a cardboard template and took it to a friend of mine to have it modified. Pictures below show the template and finished product with the Improved Racing brackets mounted with the listed McMaster Carr Bolts/Nuts. Once welded up, I drilled the required holes for the M8 bolts and got the bracket recoated by a local powder coat shop.

 

[Rogue556]

Here are some pictures of the finished product:

I drilled holes in the air deflector and installed rubber grommets for the cooler hose to run through. I like that it keeps the hose ridged and prevents unwanted movement.

The hose just barely fits underneath the two bumper/grill brackets. From the front of the vehicle, the grill hides the majority of the hose, so you really don't see them unless you are kneeled down looking up into the grill.

 

[Rogue556]

In the picture below, you can see the two Magnefine Filters running to and from the cooler.

This photo is from behind the headlight assembly, in front of the battery looking forward. The hose leaves the two filters downward and wraps down and right and loops into the Toyota OE tube assembly going through the radiator support.

You can see how the lines come out of the OE tube assembly and wrap underneath the front bumper cover mounting bracket before coming back up into the filters.

 

[Rogue556]

Here is how it looks from underneath. One of the lines is zip tied to the power steering hose/line to keep it held in place. Probably not needed, but I had zip ties laying around anyway.

This is a shot from the engine bay of the hoses running into and out of the radiator, for those confused on what the new parts look like installed.

 

[Rogue556]

Just and FYI on the installation. I was able to install everything without having to remove the front bumper cover. I only had to remove the cover over the radiator support and the front bumper cover/grill bracket on top on the driver side. Everything fit perfect for the most part.

 

[Rednexus]

One tidbit I'll add here is that IMO the stock transmission cooling problems are just as much due to the radiator as the lack of an external trans cooler (460) or the undersized OEM-style cooler (470). Despite already having a Hayden 678 in my rig, the stock radiator the temps would always still rise as soon as the TCC unlocked. Not necessarily a runaway condition (I don't think they ever got about 220F), but it was obvious the system wasn't able to shed the excess heat from the unlocked TCC.

So, this summer I installed a CSF aluminum radiator. Now, the temps barely budge with the TCC is unlocked. They might go up a couple of degrees and then stop. We pulled our 4K# camper about 4,000 miles on vacation this summer, and I've also towed my tractor (5.8K# with trailer) with the rig, so the new setup has been well-tested.

So my default recommendation for transmission cooling has changed to replacing the OEM radiator with a CSF instead, as the OEM radiators on these rigs are failure-prone anyway. Then, if you need extra cooling, go ahead and install (460) or upgrade (470) the aux trans cooler.

BTW @Rogue556, that is a super-clean install!