P0776: Pressure Control Solenoid "B" Performance (Shift Solenoid Valve SL2) Need part Number?

I have a 2012 AT V6 Tacoma with 250k+ miles on it that my son is driving. The truck started jump a few months back whenever you shifted out of park to either drive or reverse. Now it seems to be having an issue with shifting back up sometimes after you need to get on the brakes a little harder than normal. It will drop down to either 3rd or 4th with the RPMs around 3k and can't shift back up. The only way to resolve it is to pull over and turn the engine off. Once you turn it back on its fine. At least until the next time. Stopped by O'Reilly's to see what code it was generating: P0776: Pressure Control Solenoid "B" Performance (Shift Solenoid Valve SL2).

I've checked the fluid and it is at the right level. After reading through a number of post on here I feel that replacing the SL2 solenoid wouldn't hurt anything at this point with the mileage this truck has. The AT trans fluids has never been changed or flushed. I heard and read not to do it because there is a chance you could make it worse. If that's the case I'm good with that and apparently bigger steps are needed anyways.
Every time I think I have located the right solenoid online it ends up referencing one of the other solenoids (S1, S2, SL1, SLT, SLU, or SR) in the description.

I appreciate any help or direction anyone can provide.

BTW, from my readings it looks like I should have joined this group a long time ago.

 

@gearcruncher

 

P0776 is a troublesome code to fix and even worse with high mileage
Yes it causes limp mode
Yes it causes harsh shifts
Transmission will start off in 2nd or 3rd gear until code is cleared .
You clear the codes and the problem is back the next day .
The code can also be caused by faulty wiring going to the solenoid and then back up to the transmission computer
Do you have a digital volt ohm meter ( dvom ) and 12 volt test light ?

Limp mode is designed to get the truck to a shop to have the transmission fixed .
I suggest starting with the basics .
Take the transmission pan off and see how much junk is laying in the pan before spending money on expensive solenoids .

As mentioned above , the code can be generated by a faulty shift solenoid , however , if the hydraulic valve behind that solenoid is stuck or sticky , the computer in your truck is still going to continue to throw the same solenoid code after you replace the old solenoid with a new one .
If the fluid has never been changed , the chances of internal issues are greatly increased . The A750 series transmission likes regular transmission servicing.
what was the color of the fluid when you checked the level ?
Plan for the truck to be down for a while .
Plan for the possibility of purchasing a rebuilt or second hand transmission .

Not trying to scare you from trying to help your son and save money . Thats why Tacoma World is here .
There are a lot of diagnostic steps to fixing the code successfully
Owning your own scan tool would be a great start . All cars after 1996 use OBD2 . Scan tools are fairly cheap now .
We can probably walk you through diagnostics if you want to take a stab at it

Have you read through this post ? its a good link for reading
https://www.tacomaworld.com/threads...th-pics-for-second-gen-4-liter-trucks.289913/

 

First off let me start off by saying thank you @gearcruncher for your contributions to these forums. Your knowledge and experience has help a lot of people here and I am amazed at the level of detail you have given on the topic of this transmission. My hat goes to you sir.

Now on to my story. After reading over @gearcruncher material again and NOT skipping over the portion and the importance of checking the ATF level properly this time, I made sure I did it in temperature detect mode. And, I ended up having to pump 3.5 quarts into the pan before I could get it to a trickle state. I cycle through the gears more than a few times before I took it for a test drive. The TACO no longer "jumps" into D or R when shifting from P. I ran it through it's paces while driving. I got it up to a number of speeds between 45-70 and got on the brakes and then back on the gas again. No issues. I stop at the auto parts store to see if it threw a code by chance and it did not. I plan to drive it throughout the weekend to verify no damage has been done.

So, on to the million dollar questions. I was able to locate the SL2 solenoid that I picked up before I shamelessly discovered the ATF was drastically low along with a new filter. I plan to take the solenoid back as long as no issues show up over the weekend.
Question #1 - Should I drop the pan, clean the magnets, replace the filter, and top it off with ATF? Question #2 - Do question 1 and this time cycle through ATF by draining a number of times until it looks clean(er)? Question #3 - Or, should I not press my luck and leave it as is to avoid the possibility of causing issues by replacing the old ATF that I don't believe has ever been serviced? This TACO has 264k+ miles on it.

And now the Billion dollar Question that is really puzzling me. How did it loose 3.5 quarts (a little less due getting it to a trickle)? Theres no way its been this low since it left the factory. There is no leaks that I have found. And, even if there was I would think it would loose more than the volume that sits in the pan. Am I thinking correctly here? My suspension is that someone drained the ATF for some reason. Maybe thinking it was the engine oil?

Anyhow, I appreciate all the help and direction here. Let this be a lesson for all you kids out there. Do not assume your ATF level is fine without checking it with engine running and at the right temperature.

 

This is good news . You dodged a bullet . Low on fluid will cause P0776
I always diagnose assuming the transmission was full of fluid .A bad habit on my part

Going back to the basics helped you .
Very happy you checked the fluid first .
Where did the fluid go ?
Your guess is as good as mine .
If there is no signs of leaking under the truck , check for transmission fluid oil floating in the radiator .
The above can happen .

Your next step .
Take the pan and filter off , clean the magnets and put it back together .
You are taking the pan off to prevent the new fluid with super detergents from removing the junk off the bottom of the pan and forcing that junk through the valve body .
https://www.tacomaworld.com/threads...e-2nd-gen-transmission-pan-and-filter.726329/
Add 1 bottle of Lubeguard platinum , Fill the transmission back up and drive it for 6 months .

If all is good after 6 months , you can then change out the old transmission fluid thats inside the torque converter .

 

I dropped the pan, replaced the filter, cleaned the magnets and the pan, and added a bottle of Lubeguard. And to my surprise everything looked really good. Barely any metal shavings in the fluid or on the magnets. Fluid was darker than one would like of course but after doing this and topping it off before it is much cleaner now.

MYSTERY SOLVED!

When I was done with all this I decided to look over everything else with the TACO. What did I find??? Was there ATF in the coolant???? NO! Too much motor oil in the engine. My suspension was correct. My son took it upon himself to change his oil and ended up draining the ATF instead of the oil and adding more oil.


Thank god I was able to figure this out before things got really bad.

Lesson to myself. Don't ever tell your son that he can't miss the oil drain bolt under the truck without actually pointing it out to him.

 

Oh, and to close the loop on the part number for the SL2 solenoid on the A750E transmission it is D147420B.

 

This thread was very helpful! I bought my son a 2010 Tacoma as his first truck. He's been driving it almost a year when the P0776 code came up along with another one for solenoid D being stuck. After reading this thread and much deliberation I decided to do a drain and fill. To our surprise only 1.5 liters came out. We ended up adding a full 4 liters after several attempts of getting enough fluid in. Finally we were able to get the overflow to drain out some excess until we got to a steady drip. The codes cleared and the hard shifts stopped for now.

If this does fix the issue and there wasn't too much damage done I think this is a testament to Toyota. I hear horror stories about Ford and GM transmissions from the 2010's. Thanks for this post and all of the really informative responses, I think it saved me a lot of heartache and unnecessary repairs.