02 XtraCab w/ P0770 Code

hi all-

first time poster but have read many helpful posts for a while now. Looking to get some input on my 02 XtraCab- has 220k miles, purchased in 2016 with no known major upgrades/major part replacements/repair work done.

I've owned the truck for 6 years and its only ever required ongoing basic maintenance work, has ran like a champ throughout many New England harsh seasons. I took it on a 300 mile trip to upstate a month ago. On the way, i put it on cruise control and noticed the automatic shifting into 5th gear on major upslopes was slow and sporadic. The truck seemed confused as to what gear it should be in. Drove fine after that and didn't throw any lights. On the return, after a smooth drive, the check engine light came on. After driving another 100 total miles, i brought it to a Toyota Dealership as my local mechanic referred me there for tranny work. They read it as a P0770 - Solenoid E issue and stated my only option was a full tranny replacement @ $8k. I plan to get a 2nd pair of eyes on it from a local tranny shop.

That being said, I've read alot about how this code can mean serious trouble. I'm not at the point where I want to put in $8k, or even $4k for a full tranny rebuild, as i'd want to invest in another Taco that would last a long time. If it turns out that i need to replace the tranny- would you a) do it knowing the truck hopefully should be reliable for a few more years b) sell it, and use the cost i'd sick into a tranny into a truck that requires less work?

Sorry for the novel and appreciate the thoughts- Tim

 

first, @gearcruncher

second, the A340 is a 4 speed, not a 5 speed auto. what you are "feeling" is the lockup torque converter "unlocking" so-to-speak and allowing it to spin faster to allow the engine to rev and get the fluid moving to get the trans spinning more (bad description but my simple mind process of how it works).

I'm no expert but it could just need a solenoid(s) replaced?

 

Yeah, I’d pump the brakes so to speak before replacement. Mine once, and I mean once, threw a solenoid code and it never returned. I was driving around town normally, felt some odd shifting, pulled the codes myself - reset - it never reappeared.

What’s the condition and level of your ATF fluid? Are you checking it on level ground after it has warmed up fully? How old is the fluid? Have you ever dropped the pan and replaced the screen (filter)?

These trucks with auto trans like to take hills a certain way. Any relatively steep and sustained grade, I turn overdrive OFF and let her eat. Bring the RPMs up; your ATF will stay cooler and you will have more power for the climb. Turn OD back on at the crest of the hill. My ECT always stays on also, and I can definitely feel the difference with it off. It just changes the shift points but it helps.

 

If you are changing your transmission fluid on a regular basis , you have a good chance of saving your transmission .
With 220k on the clock , I have my fingers crossed you have clean fluid in that transmission .
https://www.tacomaworld.com/threads...sions-write-up-your-4-speed-automatic.325531/

The fix https://www.tacomaworld.com/threads/sonnax-zip-kit-a340-late-installation.435019/#post-14714790