GX460 P2714 P0761 Ultimate Summary and Hope For A Fix Thread

[Biginboca]

So I’m back with something maybe relevant here from my AI. I asked it what the safe operating range is for the Idemitsu WS fluid I’m running now and I think the answer may be of interest:

“The lab specs on Idemitsu TLS-LV (the WS-spec fluid) bracket a much wider range than your transmission will ever see: pour point of -54°C and Brookfield viscosity at -40°C of 6,900  on the cold end, and flash point around 170°C / 338°F on the hot end. Neither is your practical limit.
What actually matters in the truck:
• 160–200°F — normal operating range. Where the A760F lives on a typical drive.
• 200–220°F — hot but acceptable. Towing, sustained grades, stop-and-go in August. Fluid life shortens but nothing is being damaged.
• 220–240°F — caution. Oxidation accelerates sharply here. Rule of thumb: every 20°F above about 175°F roughly halves remaining fluid life.
• 250°F+ — damage territory. Seals harden, clutch friction material starts to glaze, varnish forms.
• 275°F+ — you’re cooking clutches. This is where transmissions die.

Idemitsu specifically claims strong oxidation and thermal breakdown resistance, plus seal conditioning that reduces the risk of leaks from seal shrinkage and hardening — that last part is relevant to you given the reseal work from the AT205.

The number worth watching: if you’re ever pulling a trailer in summer heat, log the ATF temp PID on a long run. Sustained readings above 220°F would be the argument for an auxiliary cooler. The GX’s factory cooling is adequate for unloaded driving but has limited margin under load in a hot climate.”

 

[BC11SVT]

So I’m back with something maybe relevant here from my AI. I asked it what the safe operating range is for the Idemitsu WS fluid I’m running now and I think the answer may be of interest:

“The lab specs on Idemitsu TLS-LV (the WS-spec fluid) bracket a much wider range than your transmission will ever see: pour point of -54°C and Brookfield viscosity at -40°C of 6,900  on the cold end, and flash point around 170°C / 338°F on the hot end. Neither is your practical limit.
What actually matters in the truck:
• 160–200°F — normal operating range. Where the A760F lives on a typical drive.
• 200–220°F — hot but acceptable. Towing, sustained grades, stop-and-go in August. Fluid life shortens but nothing is being damaged.
• 220–240°F — caution. Oxidation accelerates sharply here. Rule of thumb: every 20°F above about 175°F roughly halves remaining fluid life.
• 250°F+ — damage territory. Seals harden, clutch friction material starts to glaze, varnish forms.
• 275°F+ — you’re cooking clutches. This is where transmissions die.

Idemitsu specifically claims strong oxidation and thermal breakdown resistance, plus seal conditioning that reduces the risk of leaks from seal shrinkage and hardening — that last part is relevant to you given the reseal work from the AT205.

The number worth watching: if you’re ever pulling a trailer in summer heat, log the ATF temp PID on a long run. Sustained readings above 220°F would be the argument for an auxiliary cooler. The GX’s factory cooling is adequate for unloaded driving but has limited margin under load in a hot climate.”

Now go ask AI to correlate transmission temperatures with seal aging and how much seal aging is slowed running @ 170 degrees vs. 210 degrees.

 

[gsi18867]

Now go ask AI to correlate transmission temperatures with seal aging and how much seal aging is slowed running @ 170 degrees vs. 210 degrees.

From the back of the Hayden box:

 

[BC11SVT]

From the back of the Hayden box:

View attachment 4197331

It’s the Arrhenius factor
Seals harden at ~4.5 times the rate at 210 degrees vs. 170 degrees.

 

[gsi18867]

It’s the Arrhenius factor
Seals harden at ~4.5 times the rate at 210 degrees vs. 170 degrees.

I’d like to find another way to get more heat out of the trans. I’d like to add another cooker and possibly an electric fan. May be easier to just sell the truck once I get it sorted out and start with a new project

 

[gsi18867]

Final update: drained fluid, pulled SLT and C solenoids, swapped with known tested replacements. Double checked all connections. Refilled and set fluid per Toyota method.

Result: same 0761 putting trans into limp mode. Permanent 2714 will not clear. Solenoid C “stuck off”. Truck runs great when codes cleared.

Short test run speeds up to 60 MPH, clearing codes as soon as I see the shift 3-4 missed.

Temps higher, thermostat pinned open: Temp 1 207, Temp 2 210. I’m assuming this is from less fluid in system.

The truck is now up for sale. 175K miles. Brand new tires. Will entertain reasonable offers.

Carvana is offering $7300. I think it’s a little on the low side, but they may have an automatic plug for the transmission issue.

 

[TXMeatball]

Throwing my hat into the ring for more data/advise.
Recently purchased a '13 with 243k. Knew that 460s are kind of red headed stepchildren from the UR engine quirks and trans issues (several people in my local LC group have had issues). It was cheap and looks/drives great so here we are.
Couple days later noticed reverse "slipping" when backing into my driveway (bit of a incline). Kind of jerky where it'll catch and start moving, momentarily lose that friction, then catch again, repeating several times. Once it gets enough momentum it'll reverse like normal. Hot/cold didn't seem to affect it much, mainly the incline it's backing over. Also no CEL or anything, just a permanent DTC for P2714 that can't be cleared.
Transmission was last serviced at 144k/2020 so it's been a while. I drained/dropped the pan to replace the filter and check things. Fluid looked like it had 100k on it, magnets had normal sludge/nothing out of the ordinary. I changed the rest of the fluid by cycling gears/pulling the return cooler line so the that's all new/good.
I originally thought it'd be worn clutches but from past few pages it seems like it's the inner o-rings hardening/leaking pressure. AT205 is kind of a hack fix but if it works it works, probably add half a bottle for now. Would it also be worth it to add a Hayden 678 at this point? Seems like mine's just at the beginning of these trans failures.

Update on my AT205:
I added half a bottle (4oz) a couple weeks ago/1200 miles. Didn't seem to do much, still slips in reverse when It's at a incline. Might add the rest of the bottle. Also discovered my transfer case had like a half quart in it. Not sure if that has anything to do with this.

Reached out to a buddy who does parts and I can get a oem reman transmission for $3k after core. So I'd be ~$12kish into this thing total to have a sorted 460 with 255k on it. I fixed my main oil leak (filter housing to block o-rings) but it's still got a seep from god knows where.

 

[Rednexus]

Final update: drained fluid, pulled SLT and C solenoids, swapped with known tested replacements. Double checked all connections. Refilled and set fluid per Toyota method.

Result: same 0761 putting trans into limp mode. Permanent 2714 will not clear. Solenoid C “stuck off”. Truck runs great when codes cleared.

Short test run speeds up to 60 MPH, clearing codes as soon as I see the shift 3-4 missed.

Temps higher, thermostat pinned open: Temp 1 207, Temp 2 210. I’m assuming this is from less fluid in system.

The truck is now up for sale. 175K miles. Brand new tires. Will entertain reasonable offers.

Carvana is offering $7300. I think it’s a little on the low side, but they may have an automatic plug for the transmission issue.

Sorry it didn't work out, but you went way farther than anyone else in attempting to fix this. If anything, I think it confirmed the problem is extremely difficult to solve this problem without just putting in a reman transmission from Toyota. I do think it's possible the harness could be the issue (resistance can be checked across the various pins with a multimeter), but certainly understand that you are at or well past the "throwing in the towel" point with your rig.

Your photos of the transmission interior are certainly a "smoking gun" and IMO prove just how much havoc Toyota's trans heat management systems cause on these A760Fs. Almost to the point of being class-action litigation material .

I'd still buy a GX460 tomorrow if something happened to my 470, but the first order of business would be a complete trans service and major cooling upgrades.

 

[gsi18867]

Sorry it didn't work out, but you went way farther than anyone else in attempting to fix this. If anything, I think it confirmed the problem is extremely difficult to solve this problem without just putting in a reman transmission from Toyota. I do think it's possible the harness could be the issue (resistance can be checked across the various pins with a multimeter), but certainly understand that you are at or well past the "throwing in the towel" point with your rig.

Your photos of the transmission interior are certainly a "smoking gun" and IMO prove just how much havoc Toyota's trans heat management systems cause on these A760Fs. Almost to the point of being class-action litigation material .

I'd still buy a GX460 tomorrow if something happened to my 470, but the first order of business would be a complete trans service and major cooling upgrades.

I may try to get into the wiring more in a couple of months. For the moment, I’m tired of throwing money and time at it. It’s very hot here and Ive spent far more time working on it than I have driving it.

Currently, I have delayed reverse (by a few seconds 3-20, and what I believe is due to the coolers draining back because the thermostat is pinned open) and I have to clear the codes every time it drops below 4th gear or it won’t upshift next time. Temps never got above 188 this morning.

If I get a decent offer, I’ll take the loss on what I have in it. It’s my fault. I paid too much and didn’t do enough research before buying. If I can sell it, I’ll prob get either a 470 or go back to another 80 series.

I think there are 4 major mistakes Toyota made with this system: 1) inadequate coolers, 2) faulty thermostat, 3) poor maintenance recommendations, 4) no proper way to determine transmission fluid level. I would not take the risk of buying another 460 unless the seller had impeccable records showing transmission servicing not more than every 30-40K miles, did not have over 80K miles on it, and had never previously had an error code. All things I should have required of this purchase.

 

[BC11SVT]

Currently, I have delayed reverse (by a few seconds 3-20, and what I believe is due to the coolers draining back because the thermostat is pinned open) and I have to clear the codes every time it drops below 4th gear or it won’t upshift next time. Temps never got above 188 this morning.

I've had a Hayden 678 with pinned thermostat for almost 20,000 miles now
The cooler with pinned thermostat doesn't cause any observable reverse (or forward) delay at all for me.
That isn't your issue, IMO

 

[BC11SVT]

I think there are 4 major mistakes Toyota made with this system: 1) inadequate coolers, 2) faulty thermostat, 3) poor maintenance recommendations, 4) no proper way to determine transmission fluid level. I would not take the risk of buying another 460 unless the seller had impeccable records showing transmission servicing not more than every 30-40K miles, did not have over 80K miles on it, and had never previously had an error code. All things I should have required of this purchase.

I've said this before, but I'll say it again; I think the best way to get into a GX460 (with typical Lexus owner service history) is to get one with ~75K (or less) miles, do 3-5 drain fills in a shortish window, add a larger cooler and pin the thermostat ASAP. Follow a 30K drain/fill schedule thereafter.

The A760F failure window (with no cooler and no transmission service history) typically seems to fall in that 150-200K window, getting it at half that mileage and changing out that oxidized OEM fill out before the fluid really spirals (like it will be at 100+K) and essentially arresting seal aging/wear should provide a good long term ownership experience for almost everyone, IMO.

 

[gsi18867]

I've said this before, but I'll say it again; I think the best way to get into a GX460 (with typical Lexus owner service history) is to get one with ~75K (or less) miles, do 3-5 drain fills in a shortish window, add a larger cooler and pin the thermostat ASAP. Follow a 30K drain/fill schedule thereafter.

The A760F failure window (with no cooler and no transmission service history) typically seems to fall in that 150-200K window, getting it at half that mileage and changing out that oxidized OEM fill out before the fluid really spirals (like it will be at 100+K) and essentially arresting seal aging/wear should provide a good long term ownership experience for almost everyone, IMO.

I think the damage is done by 100K if no maintenance has been performed, maybe by 80K. Anybody with 100K+ needs to immediately perform what you prescribe here to attempt to extend the trans life.

 

[Rednexus]

If I get a decent offer, I’ll take the loss on what I have in it. It’s my fault. I paid too much and didn’t do enough research before buying. If I can sell it, I’ll prob get either a 470 or go back to another 80 series.

If you like the size/capability/comfort of a 460 but want old-school Toyota reliability, I think you'd be very happy with a 470. I still cannot believe how reliable mine is, how well it drives, how comfortable it is, how good it looks, how much power it has, how well it tows trailers, and how capable it is off-road despite being 19 years old with 207K on it. I'm obviously biased but IMO it's Toyota's best all-around SUV (which is why I'd replace it with a low-mileage GX460 if something happened to it - the GX is a great platform).

 

[gsi18867]

If you like the size/capability/comfort of a 460 but want old-school Toyota reliability, I think you'd be very happy with a 470. I still cannot believe how reliable mine is, how well it drives, how comfortable it is, how good it looks, how much power it has, how well it tows trailers, and how capable it is off-road despite being 19 years old with 207K on it. I'm obviously biased but IMO it's Toyota's best all-around SUV (which is why I'd replace it with a low-mileage GX460 if something happened to it - the GX is a great platform).

Is that a GX or a LX? Either way, I am definitely looking at the GX470. Upgraded brakes and power, along with improved comfort over the LX450 is what I was really interested in.

 

[Rednexus]

Is that a GX or a LX? Either way, I am definitely looking at the GX470. Upgraded brakes and power, along with improved comfort over the LX450 is what I was really interested in.

GX470. Very capable rig and tows just as well as it wheels. A LC100/LX470 was my first choice but a GX470 was about half the cost for a rig with similar miles/condition, so I got a GX instead. They do have some faults but none that are catastrophic. I have upgraded the rear axle in mine to an 8.2" and the front brakes, both using GX460 parts.

 

[thescreensavers]

I've said this before, but I'll say it again; I think the best way to get into a GX460 (with typical Lexus owner service history) is to get one with ~75K (or less) miles, do 3-5 drain fills in a shortish window, add a larger cooler and pin the thermostat ASAP. Follow a 30K drain/fill schedule thereafter.

The A760F failure window (with no cooler and no transmission service history) typically seems to fall in that 150-200K window, getting it at half that mileage and changing out that oxidized OEM fill out before the fluid really spirals (like it will be at 100+K) and essentially arresting seal aging/wear should provide a good long term ownership experience for almost everyone, IMO.

That's exactly what I did, I was looking at 100k + GX460s cause Toyota but upon research I ended up buying one with 48k, drain and fill immediately with a filter added as an experiment and to clean up the fluid then then a full fluid exchange. Transmission Fluid Before and After adding a Filter - https://forum.ih8mud.com/threads/transmission-fluid-before-and-after-adding-a-filter.1373325/

With the Hayden 678 and Thermostat pinned almost at 70k now everything works great, trans runs at most in the 180s and that's when it's 100F outside over black asphalt in the Florida sun. Massive improvement over the 200,210 it was running before. People need to understand that local clutch temperature is much higher than pan temps so running cooler bulk temps will always result in less trans wear, this is textbook stuff.

I preach this everyday about the benefits of added cooler and a filter setup but most think it's taboo. With routine fluid maintenance, these two added items is bar none the best preventative measures you can do.

 

[evolute]

That's exactly what I did, I was looking at 100k + GX460s cause Toyota but upon research I ended up buying one with 48k, drain and fill immediately with a filter added as an experiment and to clean up the fluid then then a full fluid exchange. Transmission Fluid Before and After adding a Filter - https://forum.ih8mud.com/threads/transmission-fluid-before-and-after-adding-a-filter.1373325/

With the Hayden 678 and Thermostat pinned almost at 70k now everything works great, trans runs at most in the 180s and that's when it's 100F outside over black asphalt in the Florida sun. Massive improvement over the 200,210 it was running before. People need to understand that local clutch temperature is much higher than pan temps so running cooler bulk temps will always result in less trans wear, this is textbook stuff.

I preach this everyday about the benefits of added cooler and a filter setup but most think it's taboo. With routine fluid maintenance, these two added items is bar none the best preventative measures you can do.

This is the move. Bought mine 6 years ago with 95k. Immediately did 3 drain and fills, pinned the thermostat and added a cooler. I’ve since done single drain and fills every 25k and am now at almost 190k with no issues at all. I am in North FL so no major cold, but does great in the dead of summer. I never see any temps on my scangauge over 200 at the torque converter.

 

[jpeterferrell]

UPDATE: I'm at about 1000 miles after adding the one bottle of AT-205 during the transmission service. No codes, no odd transmission behavior, seems to have fully restored function. At 1500 miles I'll do a drain and fill. I'm still checking periodically to see if the transmission will clear the P2714 permanent code, hoping it does that by 1500 miles or so.

I'm going to get an OTT tune this week to improve some transmission behavior annoyances, and I've ordered the factory parts to put in the OEM transmission cooler in. I'm trying to keep this rig as factory as possible, so the OEM cooler is my way to go. I'm not going to pin the thermostat unless I can come up with a good reason to. I'm also mentally budgeting for a $7500 rebuild job in case things grenade (Hawaii prices are brutal for this kind of thing) while I'm here, but if I can possibly keep it going for 10k miles or so I'll get back to the mainland and it'll be a lot easier to source something to fix the issue.

Otherwise, the truck is running great. I'm going to do sway bar bushings and end links, shocks and struts, and throw the new fan clutch/serpentine belt/idler and tensioner on. Plus I have some odds and ends (fender liners, door lock actuator, factory A/C blower motor) to take care of over the next few months, but the AT-205 seems to have worked a borderline miracle!

 

[Biginboca]

UPDATE: I'm at about 1000 miles after adding the one bottle of AT-205 during the transmission service. No codes, no odd transmission behavior, seems to have fully restored function. At 1500 miles I'll do a drain and fill. I'm still checking periodically to see if the transmission will clear the P2714 permanent code, hoping it does that by 1500 miles or so.

I'm going to get an OTT tune this week to improve some transmission behavior annoyances, and I've ordered the factory parts to put in the OEM transmission cooler in. I'm trying to keep this rig as factory as possible, so the OEM cooler is my way to go. I'm not going to pin the thermostat unless I can come up with a good reason to. I'm also mentally budgeting for a $7500 rebuild job in case things grenade (Hawaii prices are brutal for this kind of thing) while I'm here, but if I can possibly keep it going for 10k miles or so I'll get back to the mainland and it'll be a lot easier to source something to fix the issue.

Otherwise, the truck is running great. I'm going to do sway bar bushings and end links, shocks and struts, and throw the new fan clutch/serpentine belt/idler and tensioner on. Plus I have some odds and ends (fender liners, door lock actuator, factory A/C blower motor) to take care of over the next few months, but the AT-205 seems to have worked a borderline miracle!

Awesome, great to hear that! I’m now at 2200 miles since I added the AT205 and my transmission is still running flawlessly. Just as a reminder the week before I added reverse failed to engage 4 times. Now it has engaged literally hundreds of times without a single issue.

 

[Cold Iron]

UPDATE: I'm at about 1000 miles after adding the one bottle of AT-205 during the transmission service. No codes, no odd transmission behavior, seems to have fully restored function. At 1500 miles I'll do a drain and fill. I'm still checking periodically to see if the transmission will clear the P2714 permanent code, hoping it does that by 1500 miles or so.

I'm going to get an OTT tune this week to improve some transmission behavior annoyances, and I've ordered the factory parts to put in the OEM transmission cooler in. I'm trying to keep this rig as factory as possible, so the OEM cooler is my way to go. I'm not going to pin the thermostat unless I can come up with a good reason to. I'm also mentally budgeting for a $7500 rebuild job in case things grenade (Hawaii prices are brutal for this kind of thing) while I'm here, but if I can possibly keep it going for 10k miles or so I'll get back to the mainland and it'll be a lot easier to source something to fix the issue.

Otherwise, the truck is running great. I'm going to do sway bar bushings and end links, shocks and struts, and throw the new fan clutch/serpentine belt/idler and tensioner on. Plus I have some odds and ends (fender liners, door lock actuator, factory A/C blower motor) to take care of over the next few months, but the AT-205 seems to have worked a borderline miracle!

Your location shows Va. but you mention "The Rock" either way I would pin the warmer bypass open in addition to the cooler. HIGHLY recommend it.

I installed the Hayden 698 on mine. Living in the coldest State in CONUS and I didn't want to do the block the radiator in the winter with cardboard thing. And for me it was the right choice. I pin the warmer bypass open in the summer and unpin it for the winter. Really easy to do. Beginning of this year when it started to warm up I used the only steel wire that I had that fit the opening which was more like spring steel.

I tow a Polaris Ranger Northstar in the summer for sporting clays events which is ~2K pounds with the trailer. I only monitor temps when towing. Couple of weeks ago went to a club 2.5 hours away and noticed pan temps were hanging around 190° and TC went up to 210° - 220° going up and down the bluffs and hills. Then remembered the spring steel I used to pin it. Climbed under it once I got home and sure enough the pin was gone, it must have sprung open enough to fall out. Or was pulled out when on one of the trails. So I pinned it open correctly with a cotter pin that fits perfectly.

Left last Wednesday for the UP of Mi. to do the Yooper Side by Side Classic shoot 8 hour drive each way just got back last night. Pan temps stayed between 175°-185° the whole time. There was a stretch of highway in Wi. where the speed limit went up to 70 so I increased my speed up to 76 and much to my surprise that 5 mph increase took the pan temp up to 190°. No need to be towing at that speed in reality so I slowed back down to 72 mph and the pan dropped to ~180°. TC temps never broke 200. Air temps were max of 71° and below the whole time both coming and going.

Without it being pinned open the ATF temps would have been a lot higher even with the Hayden cooler. Been close to 50 years since I was stationed on Oahu and speed limits were pretty low, and air temps warm but not unreasonable so. The first thing I would do is stick a cotter pin in the T-Stat warmer bypass if it was me. And I'd just leave it there all year.