2007 Lexus LX470 P0776 & P2714 Transmission Shift Issues

[EAST TN 07LX470]

Looking for suggestions on where to start with troubleshooting. I have a 2007 Lexus LX470 with ~282,000 miles. Just today when merging onto the highway at ~75% throttle the transmission failed to shift from 3rd to 4th gear. The entire way home it would shift 1-3 and slip randomly in the lower gears. Got home and pulled P0776 and P2714 from the ECT in techstream. Codes are for pressure control solenoid B & D performance or stuck off. Tried clearing codes and disconnecting the battery for ~15 minutes. Same issue after driving again. I am getting ready to check AT fluid level. I did change the AT fluid with Toyota WS fluid ~5000 miles ago. I did a 14QT drain and fill method through the cooler line method that many people have claimed success with. I also meticulously leveled the car and leveled the fluid at the overflow at ~99F.

Any suggestions on where to start troubleshooting beyond checking the fluid level is much appreciated!

I should also note that this is not the original transmission. The PO had Mr. T put a new one in for the exact same issue at ~207,000 miles. Interesting that this is happening again...

 

[EAST TN 07LX470]

I just checked fluid level at 104F and had a good stream come out which tailed off to a trickle quickly. Fluid color and smell looked perfect.

 

[2001LC]

Check AT fluid temp #1 & #2.
Check that ECT (engine coolant temp) is making 184F or more.
Assuming ECT reaching op temp:
Send AT fluid sample to black stone. If reports metals:
Place inline AT fluid filter. The "Out" hard line to hose from AT to radiator is good spot. See if you get improvement.

 

[Vthelexus]

Interested to know the outcome. I am ready to replace trans fluid with Aisin WS on a 177,000 mile 2006 LX. This thread makes me rethink my decision.

 

[EAST TN 07LX470]

Yesterday I dropped the trans pan to inspect further. Fluid, pan and magnets were all spotless. I removed the mesh/screen filter and inspected it and the oring sealing it to the valve body. I was worried the oring was not sealing properly and causing loss of pump suction. All looked good there as well. I then followed the FSM troubleshooting steps for P0776 and P2714 which instructed me to remove and test each of the solenoids on the valve body. I was able to remove all but one without dropping the valve body or front drive shaft. For that unit I did testing and cleaning as good as I could while still in the valve body. On each one I measured coil resistance, all were in spec. I then proceeded to actuate each one with a 12V source. Note that the higher resistance solenoids can be tested with a direct 12V source. The lower resistance solenoids need a separate resistance in series, the FSM specs a 21W light bulb in series. All actuated fine, I also sprayed electronic parts cleaner through the orifices on each one as I was actuating them. I didn't see any gunk in any of them. I also checked the transmission external wiring harness connector on the drivers side. It was very crusty and almost appeared to have motor oil in the connector. I've read some of the horror stories of the A750F transmissions wicking ATF through the harness and causing all kinds of electrical issues. This substance was very brown and looked/smelled to be a mixture of motor oil and dielectric grease. I sprayed out and cleaned the connector with electronics parts cleaner. I also spot checked multiple other wiring harness connectors and did not see this same substance present, thoughts here?? I do have a pretty good leak on both cam seals. This car has also had bad VCG leaks in the past. Plan on addressing the cam seal leaks during the timing belt job.... not looking forward to pulling the cams for that. I then buttoned up the solenoids, filter, and transmission pan. Filled with 5 quarts of fresh Toyota WS ATF, and leveled the fluid at ~101F using the sensor #1 temperature readout in techstream. So far it seems to be acting fine, we drove ~80 miles yesterday at various speeds with no issues and no pending or active DTC's in techstream. Will do another ~80 miles or so today towing the boat. Fingers crossed that it behaves.

One other interesting item to note is that I occasionally have delayed drive engagement when shifting quickly from P to D. This does not occur in any other shifting pattern. I was able to get it to do this once yesterday even after the above steps were taken. This only happens ~1 in every 20-30 drive cycles.

The one item I was not able to check per the FSM is the transmission line pressure. I don't have a guage or line set to connect to the transmission in the manner it wanted.

I will keep this thread updated with how things hold up.

FSM troubleshooting for those two DTC's attached.

 

[EAST TN 07LX470]

Check AT fluid temp #1 & #2.
Check that ECT (engine coolant temp) is making 184F or more.
Assuming ECT reaching op temp:
Send AT fluid sample to black stone. If reports metals:
Place inline AT fluid filter. The "Out" hard line to hose from AT to radiator is good spot. See if you get improvement.
View attachment 3981007

Temps were fine when having the issue on both sensors #1 and #2. I never saw anything above 135F when driving close to the house and watching shifting in techstream. That was after ~20 minutes of driving. ECT was ~190-195F during testing. The fluid is new with no visible contaminants, magnets had zero build up on them as well. If the issue persists I may send a sample off. I don't see a need for a filter at this point as well. Even when I changed the fluid the first time the transmission only had ~75k miles on it and the fluid looked perfect with very minor build up on the magnets. I am curious, would an inline filter like that not add some flow restriction? See my overall thread reply for steps taken that seem to have things acting normally for now.

 

[2001LC]

The Magnefine ATF filter. Is designed, to allow proper (easy) flow. IIRC, its filter medium, filters to 50 mic, and its magnet, catches to under 3 microns.

A sample of your ATF, will let you know, if you'd gain any benefit, by filtering.

 

[EAST TN 07LX470]

Well we ended up driving ~40 miles unloaded and ~60 miles towing ~4000 lbs yesterday and everything worked great!

 

[2001LC]

Well we ended up driving ~40 miles unloaded and ~60 miles towing ~4000 lbs yesterday and everything worked great!

Still, all good I hope?

 

[EAST TN 07LX470]

Still, all good I hope?

All good still! I've driven ~3k miles since fixing the issue as well.

 

[2001LC]

All good still! I've driven ~3k miles since fixing the issue as well.

Do you have any pictures of the oil substance, you found within the A/T wire housing block?

I've started a thread, to compile these pictures. It will lead into A/T shifting symptoms, PM and fixes.

Post in thread 'Alert, Alert, Alert----- Transmission valve body wire housing block! --- Have you looked into yours? Capillary action drawing ATF in!'

Nov 24, 2025

That blue oxidation is coolant induced. It happens frequently to the 80s, because the heater bypass hose (AKA PHH) leaks onto the engine–transmission harness connections. Sometimes I think Toyota put them there to keep the coolant off the starter.

• Malleus

It is highly likely, it is capillary action wicking ATF fluid from A/T. That this fluid, is then resulting in crossover voltage bleed, within the wire housing block from pin to pin. Inhibiting current flow between TCM and valve body solenoids. Result in shifting issues.

Your, cleaning the oily substance from pins of wire housing blocks. Stop to crossover voltage bleed. But very likely, you'll see shifting issue return. As your wires within the A/T wire harness, are likely saturated within their sheathing. Thus will enter the wire housing block, in shorter time period than before.

 

[GremlinMobile]

Nice troubleshooting and it certainly does sound like you struck paydirt when you found the oil soaked connector. I've never heard of needing auxillary tranny oil filters on these vehicles, so I was very surprised that that was recommended, not once, but twice, even after you confirmed that dropping the pan revealed clean fluid.

 

[EAST TN 07LX470]

Do you have any pictures of the oil substance, you found within the A/T wire housing block?

I've started a thread, to compile these pictures. It will lead into A/T shifting symptoms, PM and fixes.

Post in thread 'Alert, Alert, Alert----- Transmission valve body wire housing block! --- Have you looked into yours? Capillary action drawing ATF in!'

Nov 24, 2025

That blue oxidation is coolant induced. It happens frequently to the 80s, because the heater bypass hose (AKA PHH) leaks onto the engine–transmission harness connections. Sometimes I think Toyota put them there to keep the coolant off the starter.

• Malleus

It is highly likely, it is capillary action wicking ATF fluid from A/T. That this fluid, is then resulting in crossover voltage bleed, within the wire housing block from pin to pin. Inhibiting current flow between TCM and valve body solenoids. Result in shifting issues.

Your, cleaning the oily substance from pins of wire housing blocks. Stop to crossover voltage bleed. But very likely, you'll see shifting issue return. As your wires within the A/T wire harness, are likely saturated within their sheathing. Thus will enter the wire housing block, in shorter time period than before.

No pictures unfortunately like I mentioned in the other thread. My oily substance was identical to the pictures in that thread. I suspect the issue will return if it is capillary action wicking either oil or ATF into the harness. I will try to inspect and take pictures if it returns.

 

[EAST TN 07LX470]

Nice troubleshooting and it certainly does sound like you struck paydirt when you found the oil soaked connector. I've never heard of needing auxillary tranny oil filters on these vehicles, so I was very surprised that that was recommended, not once, but twice, even after you confirmed that dropping the pan revealed clean fluid.

Yeah I would be very suspect of adding an aux filter to these transmissions. My fluid is and always has been absolutely spotless. These units are very reliable even with minimal maintenance or added filtering.

 

[2001LC]

To help @GremlinMobile and you @EAST TN 07LX470. Understand, the reason I suggested and inline ATF filter. I too have been working on similar shifting, DTC and brown goo in A/T wire housing block. I sent sample of its 5K miles very clean looking AFT, to Blackstone for analysis. Which showed, high level of insoluble for mileage. The picture of inline filter above came from that (a 07LX also), added after analysis and a fresh 12 qt ATF flush.

Depending on how long, your issue was present. You to could also have elevated levels of insoluble. Some being iron, which increase valve body wear.

It's very likely shifting issue was bough on, by solenoids not function properly. Due to goo in wire housing block, effecting current flow between TCM & valve body solenoids. Which delays and hard shift, was likely hard on transmission. Resulting in higher than normal internal wear. A/T shifting condition, may have been going on for thousands of miles in my case. Just to subtle, to notice by the primary driver. Perhaps in yours also.

I did notice shift delay with bump on engagement. I found I could tiger delay in shift engagement condition and worsen it. Make unmistakable a A/T issues. By shifting between R & D repeatedly. The more I shifted R-D, the worst and would only then set off DTC.

First thing I did, was glance at A/T wires, but only externally. I also check level, which was okay. No flow at 97F from check plug. Than ran A/T #1 temp up a bit more, to see flow. ~105F raise level, to see flow from check plug. I took small sample (1/2 bottle) of that flow from A/T check plug and sent to BlackStone for analysis.

Once I got ATF analysis report back and saw high insoluble. I flushed that 5K ATF out, and installed inline filter. I ran this fresh new fluid, for about ~500 miles and retested. Analysis was better, but still insoluble a bit high on one metals, lead. But iron, this sample analysis was normal. BlackStone felt, it was likely residual leftover from last flush. The inline filters magnet, did its job catching iron. Which was my biggest concern. I will be flushing again. Along with cleaning the pan, valve body. I'll not be keeping inline filter indefinitely. Just until all good ATF Analysis.

I use this filter in my shop often, to filter various fluids (AHC, ATF, EvapoRust, CRC Smart washer cleaning solution, etc.). Fluid flows through as fast as I poor in. They have no appreciable flow restriction. it's it's magnets doing most of the work. I actual pre-filter with layers of CRC SM OZZy mats. The inline Magnefine filter, is more to grab iron from my solution. Works great for EvapoRust, to extend usefull life.
Here's my Magnefine gravity feed filter sink set-up. Flow out fast and easy.

Gary below in center of drain, is my 5 layers pre-filters. Which without, even dirty solution flows through inline ATF filter very fast. Only real restriction is 3/8"

If you've ever flush transmission by it's own pump, in the 4.7 VVt with engine idle cold at ~1,500 RPM. You get a good idea of A/T fluid flow rate.
I've not actually timed. But seem to fill catch bucket at same rate as my gravity feed from through inline sink filter alone. Even dirty solution in my sink, flow fast. So I don't see issue with inline filter causing flow issue through A/T. It is what their designed for.

 

[EAST TN 07LX470]

To help @GremlinMobile and you @EAST TN 07LX470. Understand, the reason I suggested and inline ATF filter. I too have been working on similar shifting, DTC and brown goo in A/T wire housing block. I sent sample of its 5K miles very clean looking AFT, to Blackstone for analysis. Which showed, high level of insoluble for mileage. The picture of inline filter above came from that (a 07LX also), added after analysis and a fresh 12 qt ATF flush.

Depending on how long, your issue was present. You to could also have elevated levels of insoluble. Some being iron, which increase valve body wear.

It's very likely shifting issue was bough on, by solenoids not function properly. Due to goo in wire housing block, effecting current flow between TCM & valve body solenoids. Which delays and hard shift, was likely hard on transmission. Resulting in higher than normal internal wear. A/T shifting condition, may have been going on for thousands of miles in my case. Just to subtle, to notice by the primary driver. Perhaps in yours also.

I did notice shift delay with bump on engagement. I found I could tiger delay in shift engagement condition and worsen it. Make unmistakable a A/T issues. By shifting between R & D repeatedly. The more I shifted R-D, the worst and would only then set off DTC.

First thing I did, was glance at A/T wires, but only externally. I also check level, which was okay. No flow at 97F from check plug. Than ran A/T #1 temp up a bit more, to see flow. ~105F raise level, to see flow from check plug. I took small sample (1/2 bottle) of that flow from A/T check plug and sent to BlackStone for analysis.

Once I got ATF analysis report back and saw high insoluble. I flushed that 5K ATF out, and installed inline filter. I ran this fresh new fluid, for about ~500 miles and retested. Analysis was better, but still insoluble a bit high on one metals, lead. But iron, this sample analysis was normal. BlackStone felt, it was likely residual leftover from last flush. The inline filters magnet, did its job catching iron. Which was my biggest concern. I will be flushing again. Along with cleaning the pan, valve body. I'll not be keeping inline filter indefinitely. Just until all good ATF Analysis.

I use this filter in my shop often, to filter various fluids (AHC, ATF, EvapoRust, CRC Smart washer cleaning solution, etc.). Fluid flows through as fast as I poor in. They have no appreciable flow restriction. it's it's magnets doing most of the work. I actual pre-filter with layers of CRC SM OZZy mats. The inline Magnefine filter, is more to grab iron from my solution. Works great for EvapoRust, to extend usefull life.
Here's my Magnefine gravity feed filter sink set-up. Flow out fast and easy.
View attachment 4037138
Gary below in center of drain, is my 5 layers pre-filters. Which without, even dirty solution flows through inline ATF filter very fast. Only real restriction is 3/8"
View attachment 4037142
If you've ever flush transmission by it's own pump, in the 4.7 VVt with engine idle cold at ~1,500 RPM. You get a good idea of A/T fluid flow rate.
I've not actually timed. But seem to fill catch bucket at same rate as my gravity feed from through inline sink filter alone. Even dirty solution in my sink, flow fast. So I don't see issue with inline filter causing flow issue through A/T. It is what their designed for.

The videos I have seen of the magnefine filters cut open show that they have a traditional filter media in the can with a powerful magnet at the inlet side of the can to catch particles before making it to the filter media. I suspect there is some level of flow restriction with a filter like this. How much, I am not sure. Nor am I sure on long term impacts to transmission operation. It would be interesting to see the level of pressure drop across the filter to make an evidence based analysis of impacts. I personally would not use a series element in the flow path until seeing that data. I would be more inclined to use something like this in a slip stream or bypass filtering setup where it is placed in parallel with the main flow path to ensure no flow obstruction. Similar to the bypass oil filter kits that are becoming more popular in the diesel engine world.

The bypass or slip stream configuration is exactly how we setup large scale filtration for extra fine particles in our process cooling water and cooling/lubrication oil systems where I work to ensure no impacts on system flow. We do have series filtration for larger particles that don't cause flow restrictions due to the larger filter media.

However, I may be making something out of nothing since I dont have any actual data to evaluate. I would love for my gut feeling to be proven wrong and know that the pros outweigh the cons on this.

Please let me know if there is any published data that you have seen on these.