code P0770

I have a ' 97 with the 3.4 4WD. Went on a camping trip, last weekend. At some point on the way to camp, it threw the code. I reset it and it was fine. Then, every time after I started driving my truck for a few minutes to run around and on the way back home it would throw the code, again. Now, that I'm back to daily driving it's been fine and hasn't thrown the code, since I've been home. Any clue as to why it threw the code? I changed the Trans fluid the weekend before.

 

That code is for the torque converter clutch not locking up when the PCM commands it on, could be a valve hanging up.

 

Kinda strange that it started after I drained and refilled the fluid. Seems to be working fine. I just noticed today that it only throws the code while at highway speeds. Today was the first time it threw the code, since I got back from the trip. But it was also the first time that I've been on the freeway, since the trip.

 

I mean best case it's a valve or solenoid hanging up, worst case the torque converter clutch or one of the clutches in the transmission is failing.
How many miles on it?
@gearcruncher may be able to tell you more, he has a writeup thread for the A340 although alot of the external links are broken.
https://www.tacomaworld.com/threads...sions-write-up-your-4-speed-automatic.325531/

 

Dm93 is bang on the money .
Mileage plays a huge part in this .
In your first post , you mentioned changing the transmission fluid ?
Did you have the pan off to clean the screen , magnets and transmission pan ? This is very important ?

Its going to throw the code at highway speeds because thats when the computer in your truck commands the coverter to lock up .
When its cold in the morning , the converter will not come on unless you are above 3rd gear , the engine and transmission are both at operating temps and you dont have a foot on the brake pedal .

Need more info for sure