Transmission- 5 Speed automatic write up with pics for second gen 4 liter trucks

Wondering why the first mechanic didn't install the shift kit that eliminates the converter issue ?
Did he warranty his work ?
The low pressure issue can be fixed from the valve body
http://www.sonnax.com/units/250-A750F#ac3
Dealerships dont fix transmissions , they just remove and replace with new

 

First mechanic wasn't really a "transmission" guy. Parts only warranty. At that time I wasn't sure what was causing the issue. The truck was lunging forward sometimes after being driven at speeds greater than 50 mph and stopping at a red light. He said it appeared that the transmission wasn't letting go of the higher gear until it came to a full stop. It would then release (causing the lunge I felt). That got better after he made the 2 repairs but the shudder hasn't. What is the cost of the valve body you mentioned?

 

hard to believe, but this is the truth. its crazy

 

Slu solenoid is circled in blue. Need to loosen bolt circled in yellow to remove retaining pin at the red arrow. Then you can remove the slu solenoid enough to access the Allen key inside to turn it in. I also filled with valvoline synthetic atf, added 15oz lubegard and dr. tranny instant shudder fix. Truck honestly shifts better now than it ever has. @gearcruncher. Feel free to steal photo and add to original post or as needed.

 

How far did you turn it? And clockwise or counter?

 

I did one full turn in (clockwise) this was about a week ago. Still happy with the results. I might end up backing it out a quarter turn as the tc really engages well now maybe too well. I also recommend resetting shift points etc by disconnecting the battery for half hour or so

 

What does this do? Up the line pressure?

 

Slu solenoid is lock up control

 

I'm asking about the screw you turned

 

I turned the screw in the slu solenoid. Basically it changes how how tc engages and what it takes to fully engage/disengage. Over turning it will make it so it locks up too much for instance

 

Are we talking about lockup timing or force? These transmissions have a ridiculously soft lockup.

 

I have to refer to @gearcruncher for this info, he knows more than I do about the technical aspect of what the screw does.

 

1/4 turn , anything more than that and the shift into lock up becomes very aggressive . Not so bad with transmissions that only lock up in 4th gear but if you get a partial lock up in 2nd and 3rd , its going to cause some drive ability issues from the butt dyno.

Turning the screw clockwise 1/4 turn increases converter application pressure by 30 % . With this said , the only time you should increase converter lock up pressure is when you are trying to fix a converter shudder . Keep in mind that these trucks are designed to please everybody when you purchase the truck from the dealer . Good for grandpa on a Sunday drive or the soccer mom . They shift smooth and smooth equals slip/ heat .
With this said , and if you are planning to keep the truck , you can tailor any upshift or downshift to what you desire .
Best time to make a modification to shift quality is when you are due for a fluid and filter service

 

@gearcruncher
I really appreciate your threads over the years.
I only did transmissions for a few years a lifetime ago. But may have this truck for a long time. Things have changed alot since I've had one open last.
Thanks to your help I hope I don't have to open mine anytime soon.

 

gearcruncher:
Thanks I read your post thread #72


Toyota A750E/F with Multiple Solenoid Circuit Faults
Toyota Tundra, 4Runner, Tacoma, Sequoia and FJ Cruiser equipped with the A750 transmission may exhibit a complaint of multiple transmission solenoid electrical circuit faults set. Typically, to have multiple solenoid electrical faults indicates that there is a power loss or ground problems, possible compromised wiring harness (pinched, broken or melted0, or a connector is not plugged in all the way or completely disconnected. In this case, the cause may be, a bad weather pack seal on the harness side connector of the transmission case connector allowing moisture to corrode the male terminals and or deteriorating them. It is not uncommon to remove the external harness connector (female) and see the male terminals from the case connector, as shown in Figure 1, still stuck in the harness connector when this happens.



To correct this condition, replace the transmission case connector, which is part of the internal harness, and clean the terminals in the female external harness connector. Install a small amount of dielectric grease into the connector and a small amount of silicone sealant on the weather pack seal to prevent moisture.

Internal Harness (04-4Runner, Land Cruiser): 82125-35130

Internal Harness (05-Sequoia, Land Cruiser, Tundra, Tacoma): 82125-35150

Note: Contact your local dealer for vehicles other than shown above.

Did you find this helpful? Comment below. Thanks!

https://www.atsg.us/atsg/blog/toyotaa750efmultiplesolenoidcircuitfaults/


I was getting fault codes P0986 & P0776 and it turned out that male pins #s 6-8 were corroded in the internal harness; had the internal harness replaced but the outside female connector still had corrosion. I cleaned the female sockets several times used small diameter welding tip cleaners but could not get to the metal sockets sufficiently: after researching further realized the black plastic cover on the female harness end will pop off and the individual sockets can be removed/cleaned and /or replaced. I purchase and replacement female harness end part number 90980-12293 ($19) just to see how the female connector and terminal sockets worked, the individual terminal wires part number 82998-24250 can be used to replaced corroded sockets but i assume should spliced and soldered which I have not had to do yet, thankfully. Right now the issues seems to be solved by removing the black plastic cap on the female harness end and cleaning with the tip cleaner(tried not to use too big diameter, to avoid egging out the socket). See photos below.
Thanks for your posts, they are very helpful.

 

Thanks for the info and pictures . I am sure your pictures and info will someday assist many others . Much appreciated
Reddogtacoma .

 

http://www.atraonline.com/gears/2010/2010-04/2010_4_4.pdf

 

Well Shit!
I've been changing my own oil (and everyone else's) for over thirty years and last night I drained my tranny. My wife said "that's what you get for working on your truck after nine beers", my reply was "that was the problem, I hadn't had a beer". I did it right after work.
I wondered why the oil dipstick read really high, but had building project on my mind and was rushing to get to that one before the light ran out. I drove to work today and it was acting funking, thought it was a fluke. I put maybe 10 mild miles on it, hopefully didn't do too much damage.
Anyway, thanks for the write up, saved my ass, hopefully saved my tranny!

 

Ouch! Hope it works out ok for you. Keep us posted.

 

I actually meant to reply to this thread: https://www.tacomaworld.com/threads/how-to-drain-refill-automatic-transmission.63851/
But I've prb had nine or so beers and 15 threads open at the same time. But anyway, thanks gearcruncher for taking the time!