Do GX 460's have transmission problems? Should I run away? (3 Viewers)

[Import Driver]

I'm seriously considering selling my Tacoma and LX 470 and buying a GX 460.

But I started reading about GX 460's having transmission problems. The more I research, the more common it seems. I really, really don't want to own a vehicle that is prone to trans problems! And while I am very mechanically inclined, I don't think I should have to add transmission coolers and/or do a bunch of things to hopefully, maybe prevent the inevitable. I hate feeling like I'm driving a ticking time bomb! Tacomas have been bulletproof for me at sea level in the US and at 10,000+ feet in the Andes mountains and that's the way I like it.

So... should I run from GX 460's?

 

[Rednexus]

It's easy to install a transmission cooler. If you aren't willing to put in a transmission cooler (a Hayden 678 is around $60), then yes you should run from a 460 as, IMO, it's a must have for anyone who buys one of these rigs and uses it for much more than going to the mall or soccer game.

IMO, the problem isn't the transmission itself, it's the lack of a cooler and the lack of a fluid change interval from Lexus. The A760F is actually a very similar transmission to the A750F, which is known to be extremely reliable. The difference is just about every A750F included a cooler, most of the A760Fs didn't, or it was too small. Even the A750F cooler was undersized in my 470 and I upgraded it, which was very successful in keeping temps lower.

FWIW, if my GX470 was totaled today, I'd replace it with a 460. I'd look for a sub-100K version and probably pull a sample of the trans fluid and see how cooked it is. I'd run from one with nasty trans fluid. For a non-nasty one, I'd go for a full fluid exchange with Valvoline Max Life or Mobil 1 MV ATF and install a trans cooler.

 

[r2m]

To set things straight, if you're towing, running a very heavy rig or just want that extra level of comfort knowing your trans is cool, you may need "one" (1) trans cooler, and only one. I haven't done it yet, but reading on this forum, it doesn't seem too difficult, maybe a job? Anyone want to chime in on that assessment who's done the install?
The only other thing you probably should have would be something to read your trans temperatures. I use OBDLink MX+ (https://www.amazon.com/gp/product/B07JFRFJG6/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1 ). I have an old Galaxy Note 8 that I use as a dedicated to run the app on so don't need to have it on my phone. I can run Google Maps, Spotify or what ever else on my phone and the OBD app just keeps running on the other phone by my dash.
I show my engine temp and BOTH transmission temperatures, along battery charge, other gauges, and GPS since my 35" tires don't give me the correct speed on my odometer. All this in real time.
There are other temp gauge solutions out there but this works for me and a few other on this forum.

 

[Import Driver]

It's easy to install a transmission cooler. If you aren't willing to put in a transmission cooler (a Hayden 678 is around $60), then yes you should run from a 460 as, IMO, it's a must have for anyone who buys one of these rigs and uses it for much more than going to the mall or soccer game.

IMO, the problem isn't the transmission itself, it's the lack of a cooler and the lack of a fluid change interval from Lexus. The A760F is actually a very similar transmission to the A750F, which is known to be extremely reliable. The difference is just about every A750F included a cooler, most of the A760Fs didn't, or it was too small. Even the A750F cooler was undersized in my 470 and I upgraded it, which was very successful in keeping temps lower.

FWIW, if my GX470 was totaled today, I'd replace it with a 460. I'd look for a sub-100K version and probably pull a sample of the trans fluid and see how cooked it is. I'd run from one with nasty trans fluid. For a non-nasty one, I'd go for a full fluid exchange with Valvoline Max Life or Mobil 1 MV ATF and install a trans cooler.

Thanks for the reply. That is excellent info! When you put it into perspective like that it makes sense.

To set things straight, if you're towing, running a very heavy rig or just want that extra level of comfort knowing your trans is cool, you may need "one" (1) trans cooler, and only one. I haven't done it yet, but reading on this forum, it doesn't seem too difficult, maybe a job? Anyone want to chime in on that assessment who's done the install?
The only other thing you probably should have would be something to read your trans temperatures. I use OBDLink MX+ (https://www.amazon.com/gp/product/B07JFRFJG6/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1 ). I have an old Galaxy Note 8 that I use as a dedicated to run the app on so don't need to have it on my phone. I can run Google Maps, Spotify or what ever else on my phone and the OBD app just keeps running on the other phone by my dash.
I show my engine temp and BOTH transmission temperatures, along battery charge, other gauges, and GPS since my 35" tires don't give me the correct speed on my odometer. All this in real time.
There are other temp gauge solutions out there but this works for me and a few other on this forum.

Much appreciated! I'm familiar with most of that so it's logical to me.

 

[skey44]

I don’t think transmission failures are as common as the internet makes it seem. This seems like a pretty “bulletproof truck.” Even bulletproof trucks require regular maintenance. On my 80k 2018 I have done a transmission drain and fill (easy in the driveway) and it seems purely preventive at this point. Fluid was dark in color, but this is normal. Drain and fill makes a 25% fluid change. I feel solid about it. Shifting great, no problems before. Maybe I’m a soccer dad but I do use the GX as a truck from time to time (off road, roof top carrier, light towing duties). It seems extremely reliable and robust for the “light duty” life it was designed for.

 

[rav8]

I'm seriously considering selling my Tacoma and LX 470 and buying a GX 460.

But I started reading about GX 460's having transmission problems. The more I research, the more common it seems. I really, really don't want to own a vehicle that is prone to trans problems! And while I am very mechanically inclined, I don't think I should have to add transmission coolers and/or do a bunch of things to hopefully, maybe prevent the inevitable. I hate feeling like I'm driving a ticking time bomb! Tacomas have been bulletproof for me at sea level in the US and at 10,000+ feet in the Andes mountains and that's the way I like it.

So... should I run from GX 460's?

Bought mine with 76K miles for $25K about three years ago. Will be turning over 125K miles next week and have had no issues besides an inop USB port (loose connector) and some brake fluid loss (loose fitting at caliper).
Towed 4K camper about 6K miles without a transmission cooler but watched temps and selected gear as necessary to keep in range. Towed same camper an additional 6K miles after adding an aftermarket cooler, still drives and shifts great. I'm not worried about it.
If for some reason the transmission failed tomorrow, I'd replace it with a reman and keep driving it. I already got my money's worth, everything past that is a bonus.

 

[Import Driver]

Bought mine with 76K miles for $25K about three years ago. Will be turning over 125K miles next week and have had no issues besides an inop USB port (loose connector) and some brake fluid loss (loose fitting at caliper).
Towed 4K camper about 6K miles without a transmission cooler but watched temps and selected gear as necessary to keep in range. Towed same camper an additional 6K miles after adding an aftermarket cooler, still drives and shifts great. I'm not worried about it.
If for some reason the transmission failed tomorrow, I'd replace it with a reman and keep driving it. I already got my money's worth, everything past that is a bonus.

Thanks for the reply. I do some light towing (2,000-4,000) from time to time. I always stay out of overdrive unless except for a few random occasion going down hill.

I don't mind adding an oil cooler, changing the oil, and monitoring trans temps, but I don't want to feel like I need to sell it before it blows.

I also started this thread so that others could search the topic in the future. Of course there are threads about the trans problems but they only cause more concern.

 

[Acrad]

If you monitor torque converter lockup with OBD tool that can help keep the heat down as well. Lockup can occur in 4-6th gear but in an overheat situation will force it in 3rd gear.

Monitor temps while towing and back off you have fallen out of lockup and temps are climbing

 

[Rednexus]

Isn't the overheat situation for a 3rd gear lock something like 290F, and isn't the AT Temp light triggered at 306F? If that is accurate, both are far too hot IMO and a fluid change would be required ASAP.

As mentioned above, if you keep the TC locked, really it's not big deal, even with a small cooler. Where the A750F/760F suffer is pulling a long hill or pass in 3rd gear or less where you don't get a lockup. Even with my expanded cooler, the temps tend to rise (though mine have never crested 200F with the bigger cooler - they'd hit 220F or higher unloaded). Mine got too hot pulling a pass in CO unloaded. If you are pulling a steep pass towing a trailer, I think the transmission would very quickly overheat in 2nd or 3rd gear, for a A750F or a A760F. A bigger cooler would definitely limit how hot it can get, however.

Luckily on my A750F I was able to install a manual lockup switch. I lock it in 2nd and 3rd gears while towing up big hills and do keep trans temperatures low. With the bigger cooler, I usually run ambient temp plus 80 degrees with the TC locked (170F in the summer when towing).

 

[rav8]

Isn't the overheat situation for a 3rd gear lock something like 290F, and isn't the AT Temp light triggered at 306F? If that is accurate, both are far too hot IMO and a fluid change would be required ASAP.

As mentioned above, if you keep the TC locked, really it's not big deal, even with a small cooler. Where the A750F/760F suffer is pulling a long hill or pass in 3rd gear or less where you don't get a lockup. Even with my expanded cooler, the temps tend to rise (though mine have never crested 200F with the bigger cooler - they'd hit 220F or higher unloaded). Mine got too hot pulling a pass in CO unloaded. If you are pulling a steep pass towing a trailer, I think the transmission would very quickly overheat in 2nd or 3rd gear, for a A750F or a A760F. A bigger cooler would definitely limit how hot it can get, however.

Luckily on my A750F I was able to install a manual lockup switch. I lock it in 2nd and 3rd gears while towing up big hills and do keep trans temperatures low. With the bigger cooler, I usually run ambient temp plus 80 degrees with the TC locked (170F in the summer when towing).

You have to get it pretty hot to cause damage.
My highest temp (before oil cooler was added) was 238F. I was pulling the 4K lbs camper in 4th/5th gear on a steady climb through WY/MT to the NW entrance to Yellowstone NP. This was early October but outside temps were still mid-sixties during the day. Since the cooler has gone in, highest temp was 212F while towing through Michigan in summer.

 

[r2m]

Since my mechanical knowledge of auto transmissions is minimal, what I'm seeing on this thread is that 4th and 5th gear will "lock" the torque converter so the torque converter isn't having to slip holding 1 - 3 gear?
Questions:

1. Does it also lock 6th gear?
2. When on a steep grade, (excluding off road trails) if the trans is getting hot, drop it to 4th or 5th?

Both my trans gauges usually sits around 212 to 215, with one usually being a little higher than the other, which I believe is the torque converter temp.

 

[suitcase]

I don't get the feeling there have been tons of transmission failures. I've read about the coolant valley plate leak. It sounds like a very fixable thing if it ever happens. I'm hoping I'll be fine with regular drains/refills. I have about 65k miles on my 2017. Bought with about 35k and promptly changed all the fluids to baseline everything. I think I did 3 drain/refills of the transmission fluid. I have a Bluetooth OBD reader to keep track of transmission temps. On one particularly hot summer trip going up a steep pass with a roof mounted cargo box I saw temps spike to 250F. A few times a year I'll do some mild trails. I've also had temps of maybe around 210F on highway driving 70mph+ with truck is fully loaded plus roof cargo box plus bikes on a hitch mounted rack. Last year I added an OEM AT cooler and did another drain/fill to make sure the fluid was at the proper level. The fluid didn't look too bad. On my most recent trip (again with truck packed) I saw temps in the 190-200 range. Adding the AT cooler wasn't too hard. I didn't have to remove the grill. I sorta wanted an OEM cooler because, well, OEM. But, the OEM cooler is tiny. If I were to do it again, I'd probably get something bigger. It'd be a lot cheaper too. I got the cooler from Partsouq. I think it was $220 shipped which is almost half of what US dealers were asking at the time, but still a lot more than aftermarket. I thought I read somewhere that a Land Cruiser AT cooler fits, but not sure.

 

[Rednexus]

You have to get it pretty hot to cause damage.
My highest temp (before oil cooler was added) was 238F. I was pulling the 4K lbs camper in 4th/5th gear on a steady climb through WY/MT to the NW entrance to Yellowstone NP. This was early October but outside temps were still mid-sixties during the day. Since the cooler has gone in, highest temp was 212F while towing through Michigan in summer.

I'd consider 306F when the AT/TEMP light kicks on pretty hot . I haven't seen a more up to date chart, but the charts seen to indicate damage anywhere above 240F. I would not want to run my engine at 240F and the same goes for my trans.

TCI Auto Transmission Life Expectancy - TCI® Auto

There's More To Coolers Than You Think. It's no secret that heat kills automatic transmissions. And in high-performance street-strip applications, the problem is especially acute. Small diameter torque converters coupled with stop-and-go traffic greatly increase the heat level in an automatic...

www.tciauto.com

My plumber has a 2nd-gen Tundra he pulls his work trailer with, and recently upgraded the cooler. Apparently the AT/TEMP light would come on any just about any big hill, and the fluid was disgusting.

 

[rav8]

I'd consider 306F when the AT/TEMP light kicks on pretty hot . I haven't seen a more up to date chart, but the charts seen to indicate damage anywhere above 240F. I would not want to run my engine at 240F and the same goes for my trans.
View attachment 3574573

TCI Auto Transmission Life Expectancy - TCI® Auto

There's More To Coolers Than You Think. It's no secret that heat kills automatic transmissions. And in high-performance street-strip applications, the problem is especially acute. Small diameter torque converters coupled with stop-and-go traffic greatly increase the heat level in an automatic...

www.tciauto.com

My plumber has a 2nd-gen Tundra he pulls his work trailer with, and recently upgraded the cooler. Apparently the AT/TEMP light would come on any just about any big hill, and the fluid was disgusting.

I don't disagree. That's why I monitor temp closely. By the time you get the light, anything you do is just damage control.

 

[re_guderian]

For some perspective, the denominator for that "high" failure rate is over 330,000 GX 460s running around the US... S#!t gonna fail, even on Land Cruisers. 100 series early A440F failure rate was much, much higher. FB groups amplify the echo chamber.

 

[Acrad]

@r2m - normal 4-6 lockup and 3 in overheat... you can monitor TC lockup with OBDLink like this
Add the following gauge into a dashboard ----> PID ---> Toyota, Lexus Scion ----> Engine and Electronic Controlled Transmission ----> STATUS OF THE LOCK UP
It will register with a "1" on gauge for locked and "0" for unlocked
================================================
If one wanted to drop AT temp further with an external cooler they will likely need to take the coolant loop piece out of the plumbing at the radiator.

Would I have put in a larger cooler if I had to do it over again? Perhaps.. but 5 years ago no one effectively was even discussing the external AT coolers on the GX 460.

Another point I haven't heard from some failure or OBD code points... I haven't heard "Fluid has been changed every 50-60k miles and now I have a AT issue". It generally seems stock fluid & never changed or high mileage change where it would be hard to pinpoint if issue was going to happen anyway and is a red herring.

I'm comfortable with my decision to add an external cooler and have done a complete fluid swap at around 50k miles and single drain and fills every 30k miles. Perhaps will drop the filter at 100K but still at 83k.

Here is overview of the A760F in the 460

https://lexusgxor.com/_media/a760f_460_overview.pdf

'14-'23 have a ATF thermal degradation estimate that is viewable with OBD Link or Techstream

High temperature limits

 

[Cold Iron]

Many of those posting with error codes for the transmission mention cold. Although Texas and Fl. cold are relative to the North. The cold seems to amplify already existing transmission problems. Only been looking at these since November be interesting to see if it slows down during the summer when it warms up. The 460 transmission fluid system has a warmer built into it, for a reason. Transmissions don't like cold fluid although the fluid will recover once it warms up. Fluid once cooked not so much in the recovery department. The transmission fluid chart posted above is telling and pretty much accepted as standard from what I recall.

My 13 Taco took 20 minutes to warm up in the winter. The GX only 10 minutes which is good. Although pretty mild winter this year only was in the twenties below zero twice IIRC. Starting then driving without warming lube oil and transmission fluid is never a good idea in those temps. There is a reason we didn't take the locks off the throttles of the main engines of Navy ships until lube oil hit 120°.

Will start towing 3K pounds beginning of next month through most of the summer into the fall. Like @r2m and @Acrad I use mx+ and fusion. For lockup on the display I use a solid fill for locked and bring gear to the front over it so I can see if it is hunting besides locked or unlocked.

Spent 20 years looking at hundreds of gauges at a time, I hate operating any system blind. With Fusion you can customize it to whatever works best for you, and what you want to monitor.

I'll monitor temps as I tow this summer and go from there concerning a secondary cooler. I am also worried about keeping trans fluid warm the other 6 months of the year here as well. I don't want to be that guy in a Ford with cardboard placed over the front of the grille in the winter LOL.

I'll do a drain and fill at the end of hunting season which is the end of my towing. Should have ~50K on it by then. Likely do another drain and fill at 60K which is the book interval for change if you tow. Then every 25K-30K after that. I'm really not too worried about the tranny in the GX460. Went through 2 trannies plus a rebuild on a Dodge Dakota many years ago. To get to only 120K miles with it. Like I said I'm not too worried about the GX, I will keep the transmission fluid clean however. Those that have needed a new transmission all pretty much had the original fluid in them. Or if they changed it was at really high mileage which was too late.

 

[ericm979]

Since my mechanical knowledge of auto transmissions is minimal, what I'm seeing on this thread is that 4th and 5th gear will "lock" the torque converter so the torque converter isn't having to slip holding 1 - 3 gear?
Questions:

1. Does it also lock 6th gear?
2. When on a steep grade, (excluding off road trails) if the trans is getting hot, drop it to 4th or 5th?

Both my trans gauges usually sits around 212 to 215, with one usually being a little higher than the other, which I believe is the torque converter temp.

Yep it locks in 6th. It unlocks for each shift and then after a few seconds, if the conditions are right, it locks again. If you pay attention you can hear/feel it as the engine drops a few hundred rpm. Of course if you have an OBD2 device on the dash you can also display TC lock status.

If you manually shift to 5th or 4th it may lock, if the conditions are right. It won't lock if the ECU/TCU feels that the slightly lower gear with it unlocked is called for. For example when driving up the steep mountain road I live on, if I put the shifter in 4th it won't lock the TC. It's too steep or my speed is too slow or both.

My Tundra has either the same or a very similar transmission. The Tundra owners manual says to shift to 4th when towing.

 

[r2m]

Yep it locks in 6th. It unlocks for each shift and then after a few seconds, if the conditions are right, it locks again. If you pay attention you can hear/feel it as the engine drops a few hundred rpm. Of course if you have an OBD2 device on the dash you can also display TC lock status.

If you manually shift to 5th or 4th it may lock, if the conditions are right. It won't lock if the ECU/TCU feels that the slightly lower gear with it unlocked is called for. For example when driving up the steep mountain road I live on, if I put the shifter in 4th it won't lock the TC. It's too steep or my speed is too slow or both.

My Tundra has either the same or a very similar transmission. The Tundra owners manual says to shift to 4th when towing.

For a wee bit more clarification, to "lock" into a gear, one must use manual shift, e.g.: shift and keep it in 4th or 5th or 6th gear. Having it in drive mode will not lock in any specific gear, correct?

 

[ericm979]

For a wee bit more clarification, to "lock" into a gear, one must use manual shift, e.g.: shift and keep it in 4th or 5th or 6th gear. Having it in drive mode will not lock in any specific gear, correct?

Yep. In drive the trans is free to pick the gears that it wants. In manual (sport), the gear you select is the upper limit. It won't shift to a higher gear than that but it will shift to a lower gear if it wants.

I think the programming in manual may be a little more likely to down shift but I'm not sure. If it is, it's barely noticeable.