Lexus GX460 (2 Viewers)

[josecarlos1593]

Hello everyone, I purchased a 2010 gx460 premium about 7 months ago, 4 months ago I replaced the transmission fluid and filter with WS fluid ( no flush ) (130k miles ) about a week ago the suv started acting up specially in the morning, throwing codes like P0761 P2714 C1201, and not shifting from 3 gear to 4 gear. It only does this if I don’t let the car warm up before driving. If I let the car warm up the transmission throws no codes and shifts like butter. Can anyone please help me find the issue ? Do I need a new transmission?

 

[Acrad]

P0761 / P2714 info (Post 72) - FSM info on errors

Here is one on P0761 as well

Diagnosing Solenoid Performance Faults in A761, AB60 & A960 6-Speed Transmissions

The Toyota/Lexus A761, AB60 and A960 6-speed transmissions have been showing up in shops more frequently over the last couple of years. Warranties are expiring

www.sonnax.com

"The Toyota/Lexus A761, AB60 and A960 6-speed transmissions have been showing up in shops more frequently over the last couple of years. Warranties are expiring and people seem to be hanging on to their vehicles longer these days. Even so, there are a number of different issues with these transmissions, including torque converter clutch failure that is especially chronic with AB60 Tundra applications. Common to all these units is a problem that sticks out a bit more than the others, though: On-Off solenoid mechanical fault codes. You’ll see these as P0751 S1 solenoid performance, P0756 S2 solenoid performance, P0761 S3 solenoid performance and P0766 S4 solenoid performance codes.

These types of Diagnostic Trouble Codes (DTC) set when the Transmission Control Module (TCM) commands a specific gear and an incorrect ratio is shown from the input and output speed sensors. As an aid for diagnosis, the TCM will set a DTC related to the solenoid or combination of solenoids responsible for that gear ratio. This can be a tricky situation, as the same performance codes also can set when a clutch in charge of holding the gear ratio is slipping or neutraling out. Immediately throwing new solenoids at the problem can be an expensive mistake if the clutch actually is to blame. The key to diagnosing the problem right the first time is verifying solenoid commands and gear ratios with a thorough road test and capable scan tool.

The trouble area that these three transmissions have in common relates to the feed that these solenoids are provided. On-Off solenoids typically are fed reduced pressure from a solenoid modulator valve or fed line pressure through a very small orifice to prevent flooding. Oddly enough, these 6-speed solenoids are fed regulated, non-orificed line pressure from the manual valve. You can count this as your little-known and even less-cared-for fact of the day, but it’s an extremely important one.

The significance of the unusual feed system is where our problem lies, because there is another On-Off solenoid connected to same oil circuit feeding the solenoids: the SR solenoid. This particular solenoid does not have a performance code connected to it to aid in diagnosis. The fact of the matter is that the trouble codes listed above really are of no help other than pointing us to the solenoids. The actual problem is deeper…it is the solenoid feed.

Figure 1 shows the locations of S1, S2, S3, S4 and the SR solenoid where you can see an exhaust port deeper in the bore from the SR solenoid. This port is directly below the retainer pocket for the bore plug located behind the SR solenoid (Figure 2 shows the OE bore plug and retainer removed from the valve body).

This bore plug separates solenoid feed (line pressure) and a circuit that is charged in first through fourth gears (Figure 3).

This problem area was discovered by Jeff Parlee, director of product support at Valve Body Xpress, and it was easy to see when run on the valve body test machine. As soon as the line pressure circuit was charged, oil started dumping out of the exhaust port. It was one of those “that can’t be right!” moments, and of course it is not right. Not every shop out there has a valve body test machine, so this problem can be missed very easily. A good repair for this area is an O-ringed bore plug that is threaded so it can be installed down into the bore with ease (Figure 4). The O-ring prevents solenoid feed (which we know now is line pressure) from leaking into the sump. This leak not only causes low solenoid feed, but also low line pressure that we all know is not good.

Removing the OE bore plug is where the challenge lies. Figure 5 shows the location of the retainer for this bore plug. A large paper clip and needle nose pliers can help push this bore plug out of its location starting at the exhaust port and/or the passage behind it (Figures 2 and 3). By the way, this is the one that always falls out of the casting when cleaning it, as there is no valve or spring that lives here to keep pressure on it.

I hope this overview of solenoid diagnostics has been helpful and proves that little-known and even less-cared-for facts are important to diagnosing hard-to-find problems."

 

[Acrad]

 

[Tex68w]

Impressive reply. I haven't heard of this issue but maybe it'll start to rear its ugly little head more often as these trucks start to age into their second decade and mileage climbs.

 

[LTSR]

Impressive reply. I haven't heard of this issue but maybe it'll start to rear its ugly little head more often as these trucks start to age into their second decade and mileage climbs.

you don’t know @Acrad very well. that’s a standard reply lol. we have our very own gx460 fsm in human form.

@josecarlos1593 let us know what you find. don’t disappear on us!

 

[Tex68w]

you don’t know @Acrad very well. that’s a standard reply lol. we have our very own gx460 fsm in human form.

@josecarlos1593 let us know what you find. don’t disappear on us!

I've seen his replies, this one was just very detailed and about an issue that most if not any of us were aware of.

 

[LTSR]

I've seen his replies, this one was just very detailed and about an issue that most if not any of us were aware of.

theres a lot of technical info on clublexus where most people go for this kind of stuff. mud is i think where off road focused folks tend to land.

 

[Tex68w]

theres a lot of technical info on clublexus where most people go for this kind of stuff. mud is i think where off road focused folks tend to land.

Yea I rarely poke my head in over there, too slow.

 

[r2m]

Excuse me while I have a little chuckle when you say you have to wait for your GX to warm up when you live in Florida.
Seriously, hope you get it resolved. Nothing worse than codes and electrical.

 

[josecarlos1593]

you don’t know @Acrad very well. that’s a standard reply lol. we have our very own gx460 fsm in human form.

@josecarlos1593 let us know what you find. don’t disappear on us!

I will, just that I haven’t had any luck yet, my mechanic talks about hard seals that expand when the transmission is at operating temperature, others talk about solenoid problems, others say that is fluid level. So far I replaced one of the solenoids, checked the fluid level, even added Lucas but still have the same issue.

 

[Acrad]

Does your mechanic specialize in transmissions?

 

[josecarlos1593]

Does your mechanic specialize in transmissions?

No he doesn’t, the transmission shop just told me that I need a full repair, which I’m trying to avoid because there is no way that a transmission that’s working perfectly fine after the car hits operational temperature needs a full repair. Doesn’t make sense.

 

[Acrad]

IMO: It will be difficult to find a transmission shop that won't want to do a full rebuild. If you aren't already I would be dealing with someone who specializes in Toyota or Asian vehicles.

Certainly plausible what I posted above is the cause but it is anyones guess....

 

[Acrad]

You may want to look at the output speed sensors as well

Post 31

I bought the #cheapest GX in the country (on autotrader) - ClubLexus - Lexus Forum Discussion

GX - 2nd Gen (2010-2023) - I bought the #cheapest GX in the country (on autotrader) - Update: I got screwed. Hi guys, I am a new owner of a very used but seemingly loved GX460. I needed an SUV, my previous car was a coupe. My research lead me to getting a GX for the reasons I'm sure we all know...

www.clublexus.com

Transmission OBD Codes

P0705
P0711
P0712
P0713
P0717
P0722
P0729
P0748
P0751
P0756
P0761
P0766
P0776
P0778
P0781
P0894
P0973
P0974
P0976
P0977
P0979
P0980
P0982
P0983
P0985
P0986
P2714
P2716
P2742
P2743
P2757
P2759
P2772

 

[josecarlos1593]

Update: Had to go with a new transmission, shops were charging too much to rebuild and putting a new valve body in without knowing if that was the problem,was too risky,so I decided to go with a new unit to have a piece of mind. The old one was working perfectly fine at operating temp,not skipping gears or anything, just the solenoid D stuck off and not shifting when cold.

 

[jmanscotch]

Update: Had to go with a new transmission, shops were charging too much to rebuild and putting a new valve body in without knowing if that was the problem,was too risky,so I decided to go with a new unit to have a piece of mind. The old one was working perfectly fine at operating temp,not skipping gears or anything, just the solenoid D stuck off and not shifting when cold.

Sorry to hear but maybe it was the right choice. Curious, if you don't mind sharing, how much that cost? I assume new OEM or rebuilt or ?

 

[jaycarl]

Update: Had to go with a new transmission, shops were charging too much to rebuild and putting a new valve body in without knowing if that was the problem,was too risky,so I decided to go with a new unit to have a piece of mind. The old one was working perfectly fine at operating temp,not skipping gears or anything, just the solenoid D stuck off and not shifting when cold.

A year later! How much did you pay? Where did you have it done? Where did you get the tranny?

Thanks Acrad for your info, your a great example here most don't follow.

 

[Pick]

Sorry for the old thread resurrection... but I got a P2714 on our 2011 GX460 with 160k and thought I would share some info here

I didn't have ANY issues initially with operability just the P2714 CEL (and all the accompanying lights: VSC, 4Lo, etc.) I decided to change the fluid and found it was BLACK. I ended up changing it 3 or 4 times with short jaunts around the neighborhood in-between. The light went out on my last test drive and it was running as good as it ever had.

About two weeks later the light came back on and it started shifting horribly. This time I had multiple codes (P0766, P0776, P0983 along with P2714). I've been researching for a little while but couldn't find a lot of info so I took it to a reputable transmission shop. After testing, I was told that he suspected the valve body was bad but when he pulled the pan they found metal in the bottom. He started researching parts availability and isn't having any luck finding Lexus parts or an entire transmission in stock. If he ordered the transmission, I'd be 91 on the waiting list. He said he would start looking at non-OEM options but I'm not sure that's what I want to do.

Hope to have some more info soon but this is turning out to be a real bummer

Trans Temp test mode disco:

First change comparison:

3rd change comparison:

 

[r2m]

Really sorry to hear that. Have you tried any salvage (junk) yards for a tranny?

 

[Pick]

I haven't found anything but it hasn't been an exhaustive search either... fearful that a used trans may end up with the same issue.

Love your signature... reminds me of a story that Lou Holtz told our company in a motivational speech in the late 90's:

The Dash

"The Dash" originally was an essay written by Alton Maiden, a former Notre Dame student and football player under famed coach Lou Holtz. Coa...

www.bobdowning.org