I got everything from the sonnax website that went in the valve body. The solenoids is bought from whichever toyota dealership gave the best discount at the moment.
GX460 P2714 P0761 Ultimate Summary and Hope For A Fix Thread
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BREAKING NEWS**** Check out page 6 and @BamaPaul’s info on the solenoids and Sonnex kit!!!!!
Lexus GX460 P2714 P0761 Collection of Info
Hey crew! I know many of us have been affected by this issue with some replacing their transmission at around 80-180k for $7-8k.
On all forums and groups this appears to be a mystery with pockets of info here and there. I’d like to collect all the info and hope others who properly fixed it WITHOUT buying a new transmission can let us know what the real issues is as normal Toyota dealers and Indy shops usually recommend replacing the solenoids and eventually the whole transmission for $7-8k.
Below is a summary of everything I have read over the past 6 months on this. Huge props to Castle CZ and Daniel Silver on the Facebook GX460 Repair group who both found a fix for $500-1500 to a FREE workaround by manual shifting.
Hope this helps folks out in our situation and eventually solves this thing!
Please post IF you have learned something new OR what the true fix was.
Cheers!
ISSUES
-First/Cold starts car will not shift from 3-4, throws codes P2714 and P0761 - Stuck Solenoids, check engine, VSC and 4LO come on. Happens in the first 5-15 minutes. Must pull over and erase codes.
TEMP FIXES
-Disconnect negative battery cable to reset codes once they flash, drives fine rest of day
-Buy a scan tool, pull over, erase codes, turn off, turn on and drives fine the rest of the day
-Tape up the dashboard and only drive 30 mph everyday
BETTER LONG TERM OPTION
-First/Cold starts - place car in manual shift in gear 1. Up shift around 2200-2600 rpms for the first 15 minutes. Then place in automatic for rest of the day. No codes or issues!
-This works! Beats pulling over everyday to reset codes and saves $8000
-This also appears to prove there is an issue with one or multiple sensors we can’t fully figure out yet
INITIALLY STEPS TO ADDRESS CODES
-Drain and fill transmission fluid
-Clean MAF and throttle body
-Unattached all electrical connectors related, clean and snugly connect back
-Replaced both speed sensors on the transmission part 894130C011
-Replace Solenoids
-Pray
-Take to a real good transmission shop to diagnose to properly fix and address
-Worst case = Manual shift the vehicle for the first 15 everyday OR spend $8000 on a new transmission
ULTIMATE FIX?
***BREAKING NEWS**** Check out page 6 and @BamaPaul’s info on the solenoids and Sonnex kit!!!!!
-SOME have fixed it with fluid, solenoids, MAF cleaning, throttle bottle cleaning and the Transmission Sensors replace. Others did all this and still have issues with codes and shifting
-I’ll be attempting all of the above except Solenoids to see how it goes, but manual shifting is saving me $8000 currently!
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Here is a way to test solenoid switching w 12v battery rather than checking ohms as someone mentioned. It needs to be a strong click when activated. The video shows one weak solenoid for comparison.
Here are my codes. I encourage folks to check out the Launch 2.0 code reader specifically for Toyota Lexus. It has extensive features that may approach Tech Stream. It’s about $160 on Amazon.
My issues are not shifting above 4th.
This 2010 GX460 has not been reliable like my 2 3rd gen 4Runners and 2001 LX470.
If you think this tranny problem is bad, we bought the 2010 GX in 2018 w 100k mi 1 owner Lexus serviced and lost the engine at 130k mi during Covid. Took 8 months to find a 65k mi engine that matched and cost $11,000 all in to install and that was w local guy. Toyota would have been worse.
This is my wife’s car and her dad feels so sorry for us, he’s selling us his 2022 GX w 46k mi for $30k. He’s tired of me trying to be an amateur mechanic w all my old vehicles.
This 2010 GX460 has not been reliable like my 2 3rd gen 4Runners and 2001 LX470.
If you think this tranny problem is bad, we bought the 2010 GX in 2018 w 100k mi 1 owner Lexus serviced and lost the engine at 130k mi during Covid. Took 8 months to find a 65k mi engine that matched and cost $11,000 all in to install and that was w local guy. Toyota would have been worse.
This is my wife’s car and her dad feels so sorry for us, he’s selling us his 2022 GX w 46k mi for $30k. He’s tired of me trying to be an amateur mechanic w all my old vehicles.
About to jump in fir one last try before I sell her or burn her.
Lets goooo. Im still waiting my valve body.
Pulled it apart. Check valve and spring fell out (spring was a little shorter than new one). Pulled 3 valves and replaced. Nothing to report besides slightly shorter old springs and semi flat o rings. BUT! The C1 (Sonnax for the replacement- it’s the only metal valve) was jammed in place. Had to grab and work it to get it out. So much makes sense now about why it worked great right when I took it apart before and gradually got worse each time. It was rotating back into its old worn seat where it would jam. Makes sense why the lubeguard worked at first. Makes sense that I had to rev it up to get it into reverse and why that trick was barely working lately. The C1 was jamming closed or only partially open.
Now I gotta put it back together and test this theory and add the Lucas
Now I gotta put it back together and test this theory and add the Lucas
Well, I was wrong about the C1 piston. It only contributes to forward clutch engagement, still have reverse problems. I believe that’s it for this transmission and prob the truck for me.
Knowing what you know now, would it have been less costly in both time and money to have simply gotten a remanufactured transmission?
Yes, but I took a fairly common approach to an unknown problem. Start with the cheapest/easiest potential solution and work up the ladder. I had that luxury as I have other cars and could do the work much cheaper since I did it all myself. I’m about $700 in. No idea what a mechanic would have charged, maybe $2K. If it had worked, we’d be having a different conversation.
For anybody throwing codes right now, or suffering with delayed shifts in all but reverse, I would advise to change the C1 piston. That’s it. That’s a $22 (plus gasket)repair if done themselves. My forward gears shift much better, but not perfect. If anybody has a reverse issue like I do, sell the truck or fork up the $ for a rebuild.
Does anybody else know about these? I didn’t know about them till I watched an A760F rebuild video. Turns out they can create all the problems we’ve been having, including losing reverse until warm up, especially losing reverse until warm up. But you can’t buy them. There aren’t even Toyota part numbers for them. They don’t show up on any exploded diagrams I’ve found. Only way to get them is to buy a rebuild kit.
What you circled is the brake drum check seals....the 3 o rings you see after you remove the valve body.
Not sure how much more money you want to put into it or sell it as-is and start somewhat fresher with a newer vehicle.
Given all the symptoms after a VB rebuild, it looks like you still have bleeding/sealing issues. I caved in and bought/downloaded the repair manual to help you and myself for self knowledge. Reading and applying the tables for gear shift ops, I suspect the that the sealing o orings and or molded/bonded pistons are dried up and hard causing bleed/low pressure issue to not apply the clutch(es). Pages 64-63.
If you were here in Houston/Sugar Land. I'd help you rebuild it. Aisin should have came up with a better fail safe sealing design then to tear down a transmission to replace hardened o rings and bonded/molded pistons.
Thank you very much! It looks like it’s the clutch sealing washers and clutch housing seals on page 38. Reverse requires almost 2X the fluid pressure as forward and high viscosity fluid did not help, which is why I don’t think it’s the piston seal. If I drive it long enough to gain reverse function, I slowly lose it if I sit idling too long. Two of the 3 ports are used in reverse. One for the brake and one for reverse itself. So it could potentially be 2 if the washers and/or 2 of the housing seals. High revving to gain reverse doesnt always work, particularly if the trans is very cold. That’s one reason I think it could be those seals, revving it up increases pressure through that fluid path. Theres a diagnostic trick with neutral you can try to see if you can flood the reverse piston without revving it up. It kinda works. I don’t gain full power reverse, almost like a clutch slipping. Same exact effect if I put it in drive without a warm up. But I like drive, I don’t get full power a few seconds later. The pressure doesn’t fully catch.
The reason I don’t think it’s the piston bond is that I can get full power reverse after highway speed driving. Full engagement there, full movement of the piston after the fluid thins and seals swell with heat from driving. The leak could also be in the VB plates. I’ll retorque when I replace those seals next week. I inspected them but didn’t see anything odd. I tried to order just the seals but couldn’t. So I have a kit coming from Cobra.
When I lost reverse, no amount of revving could get reverse to engage. Revving helped initially but that didn't work long for me. I pushed it down the driveway and drove it straight to the transmission shop.
Once you pull the valve body off, do an air check for the brake clutches. That will verify if you have a seal leaking issue in any of those circuits.
Reverse is engaged by applying C3, B1, and F1. Do an air check for all of them but probably pay attention more to C3 and B1. I'm not sure if you'll be able to see C3 engage since it's inside the clutch housing, but see if you hear it leak. (page 163)
Visually you can see it better or probably the only way is with the transmission disassembled, pump out and clutch housing mounted on the pump and doing an air check. (page 78)
Someone just shared this in another forum I'm on:
Best thing I've seen for a rebuild on Youtube to date!
Best thing I've seen for a rebuild on Youtube to date!
Guess what, there is another video in the series about another truck with the same issue. This one just came out today.
I Found the Perfect Truck But Here's What's Wrong
Amazon Store Front: https://www.amazon.com/shop/handy_man_eddieCheck out my instagram https://www.instagram.com/handy_man_eddie/Technical Info Channel: https...
youtu.be
The reseal kit arrived from Cobra. I did not order the kit with pistons since I am not ready to pull the trans yet and it’s a lot more $. I wanted the six seals between the case and the VB. But in the kit came the testing instructions for the solenoids. They are list the
ohms, not the voltage.
Some people have reported having a hard time finding a rebuilt valve body. I find a lot of them on ebay but not sure about the reliability. They seem a bit inexpensive compared to the $1000 or so others have reported.
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I just received a brand new OEM valve body, still sealed in the bag, I dont know if sell it for like 800-900 and go for a new transmission for like 3.4k or 3.7k or install this vb and give it a try. (I dont have a problem to put the transmission by myself)
I was testing my solenoids, since the new valve body dont come with solenoids, and all are in the spec in terms of ohm and they activated when I put 12v. Tomorrow or later I will go and grab the orings for the accumulators, the filter and gasket at the toyota dealership.
What else should I grab?
I was testing my solenoids, since the new valve body dont come with solenoids, and all are in the spec in terms of ohm and they activated when I put 12v. Tomorrow or later I will go and grab the orings for the accumulators, the filter and gasket at the toyota dealership.
What else should I grab?