Auto trans not shifting passed 3rd

The computer in your truck has to see the problem occur twice before it will set the code and place the transmission into limp mode .
We know its full on fluid now , so thats out of the way .
Can you confirm that it only trips the code when hot ? Are you using anything to watch your transmission temps ? Hows your transmission cooling system ?
My first thought is your SL2 solenoid is a little plugged up with some debris.
Use this image to identify your SL2 solenoid

 

Yes only hot

 

Grab this file . This is an aftermarket overhaul manual for your transmission . Far better than a factory manual . Enjoy . That file was expensive when these transmissions were first released .

Hit up page 16 and check out the diagnostic tree for P0776 . Its going to show you how to check for resistance . You need between 5 and 6 ohms at room temp .
Next , you can also try a voltage test .
If both those tests pass , you gotta pull the pan and inspect the SL2 solenoid to see if its full of crap .

Edit : I am pulling the file .
sorry guys but I am not dumping the file to non members ..
I will gladly pass it along to members .
If you want the file , you gotta join Tacoma World and send me a PM

 

Got it

 

Is the slt same as solenoid b and is that sonething easy to swap?

 

Under ideal conditions using Toyota,s diagnostic breakdown for solenoids , you do a resistance test next . If the resistance test fails , then we pop the pan off and have a good look at the solenoid . Solenoids can be removed and replaced fairly easy but you gotta follow the diagnostic tree in steps layed out by Toyota .
Do you have a factory repair manual for your truck ?
Do you have a digital / volt / ohm meter ?
Going to PM now

 

I have a meter but no manual. What does sonething like this gonna cost at a shop u think

 

I am working on arming you up to fix this . At this point , its easy . Read through that book where it shows the solenoids and how to test for resistance.
In a shop , minumum $500 bucks . Dealerships wont touch this type of job . Stay away from stealerships please .

 

Ok thank you. I just feel super stressed lol

 

At the same time you have the pan and filter off , you carefully check the wiring for cracks and if the insualtion is rubbing on metal anywhere . The internal wiring harness is well known for going bad causing your P0776 code . Its not uncommon for something like this to happen when a transmission service is being performed .
Why ?
The additives in your old fluid were depleted . You old fluid worked hard all its life depositing sediments to the bottom of the pan .
When you introduce new transmission fluid with fresh detergents into the transmission , the fresh detergents can lift old sediments and force them into the solenoids and valve body . Gotta be super clean

.The good news ..Both issues are an easy fix for a do it yourself guy
If the solenoid is not plugged , chances are its faulty .
Here is an aftermarket Rostra solenoid .
https://rostrapowertrain.com/products/52-0576/
Rostra also sells the internal wiring harness
https://rostrapowertrain.com/types/wire-harnesses/?makes=toyota&transmissiontypes=a750e

This job costs well over $500 in a transmission shop and dealerships would be quoting you for a new transmission $4000 .
Lets see if we can save you some cash

 

Just sbout the slt?

 

Here is an example of the factory solenoid .
Before you purchase , ask if the part number has been susperseded
https://www.toyotapartsdeal.com/oem/toyota~solenoid~assy~clutch~control~no~1~35210-50010.html

Grab a fresh pan gasket too unless yours is re-usable .
You can also grab a cork gasket from a transmission shop for 1/4 the price

https://www.toyotapartsdeal.com/par.../transmission_case_oil_pan_atm.html?pnc=35168

 

@gearcruncher

You sir are awesome. Thank you.

 

Always comes thru in a Crunch.

 

Not awesome yet gentlemen lol .
We have to wait 3 days to see if the OP is fixed or not .

 

Used to be we just waited for coloured smoke & called ‘er good.

 

Good morning Jainuss

Dude !!
Its been 4 days . Hows the transmission working ?

Well ladies and gentlemen of the jury , day 3 is over and no sign of the OP . I have to assume we got him fixed or he would be back screaming at me for wasting his money .
I suppose in the end , no news is good news

 

Quick update. ive been away for a few days sorry i have not had a chance to get back on and give an update. Was not intentional. I will drive it around for another day or two and report, thanks all and huge thank you to Gearcruncher, this guy knows his stuff.