I've got a 2000 4wd Automatic with 170k.
I've been experiencing a CEL code P0770: "Shift Solenoid E". I'm trying to decide what to do next. If anyone can help me by checking my reasoning, I would be very grateful.
1) There aren't any obvious transmission performance issues with the exception of a bit of delay when changing from N to R. It's slow to enter R, so if I press the gas immediately after shifting into R it will audibly clunk and make very jerky movements. If I wait ~2 seconds after shifting into R all is well. Other than that, there doesn't seem to be any slippage, noises, or rough shifting. The vehicle accelerates and shifts well.
2) I've reset the CEL twice in the past 3000 miles. The CEL light has come back each time, but only after 800-1000 miles and many shorter trips. It has always come back during longer road trips after driving for 300-400 miles. The CEL light seems to always come on when driving at highway speeds and, (I think) using cruise control.
3) I have never used the Overdrive On/Off button, it's been off the entire time.
4) After the first time getting the CEL, I dropped the pan, flushed the fluids via cooling hoses, and cleaned the filter and magnets. The fluid was a horrendous opaque dark dark red (nearly black). The ATF fluid may never have been changed. The magnets were covered in a layer of sludge. There were some metal shavings, but not a terrible amount and no large flecks.
5) After the CEL light is activated, the truck seems to drive with less power in the 55-80 MPH range.
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Some people here have said that P0770 is a tranny death knell, which is what has me scared. These people advise going directly for a salvaged-tranny swap.
Some people here have said that they simply ignore this code and keep on driving. We haven't heard from anyone who did this 10,000 miles later however.
Some people have had luck replacing their solenoids. Some have replaced their solenoids and seen no change.
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The service manual for this code states three potential causes:
A) Faulty solenoid.
B) Clogged valve body.
C) Faulty torque converter clutch.
I'm guessing that my issue might be B). Reasoning: the CEL takes a really long time to come on. If the solenoid was faulty, I'd be able to reactivate it much more consistently. Additionally, I'm not seeing slippage issues commonly associated with a failing Torque Converter (though, I'm not sure how I should be monitoring the "lock-up" aspect of the TCC.. how can I tell when my vehicle has locked-up the TCC/how should it perform?).
Right now I'm leaning towards taking it into a transmission shop. That said, I worry about spending ~$600-$8000 on solenoid replacement and valve body cleaning when that money could have gone directly towards a needed transmission swap.
My top priority is reliability, especially in the next 50k of the truck's life. I'm taking this truck on a 30,000 mile overloading expedition and have invested quite a bit in modifications at this point (much more than the value of the truck itself). I'd much rather spend the money to earn reliability and peace of mind, than get stuck in Colombia for two months trying to source a replacement transmission.
What would you guys do in my shoes?
1999 v6 3rd gen, 120,000 miles, elocker, automatic
Hoping I can get some guidance from the 3rd gen members who have gone down the path of p0770.
I bought the truck a month ago, (rarer 1999 with elocker, minimal rust on frame).
- the previous owner (only for less than 4 months) had recently replaced the radiator. He assured me that it was only because the radiator was leaking. His mechanic reported no pink milkshake, dropped the pan and changed the filter
- truck had always refused to shift into second when on cold startup, but would finally do so after 2 minutes of driving, less if I waited longer--read that this was pretty normal for cars to not get out of first gear in cold climates- drove without any hiccups for 2 weeks when:
- cold start, the transmission started to shift hard into all gears on city streets, right after I pulled the atx dipstick to check level (was fine). RPM's would also drop abnormally low between each gear, almost as if it was a manual and you shifted into the next gear with too little rpm's
- pulled into gas station, kept it running
- code p0770 pulled from the obd2
- after poking around for 5 minutes, got back on the road, and the hard shifting went away after another 5 minutes
- I went on driving for another 2 weeks, p0770 clearing itself once, coming back on once, and me clearing it once
- cold starts will still not get out of 1st gear until coolant temps got up
- finally, truck got p0770 one last time close to home. This time, every time I let off the gas, I heard a "thunk" from the front end. Could be low speeds, could be 30mph, every time the engine (and transmission) was under load, and I let off the gas, there was a "thunk" from what I assume is the transmission. Not super loud, not super quiet, could barely hear it over the radio. Coming to a complete stop, I would also hear "a bag of marbles" a bit.
- the next morning, on a cold start, the transmission will shift into drive, but rpm's would immediately drop, and the car will struggle to hold idle, and eventually die. Could not get out of the driveway. Car idles in park, as well as neutral and reverse, but the moment I put it in drive, idle splutters and the engine dies after 2 seconds.
- I pushed it onto the street expecting to tow it, let it idle in park for 5 minutes while I check level for transmission (okay)
- after 5 minutes, put it in park, and it held idle no problem, and was able to take it around the block, with the same behavior as the day before: hard shifting into 2nd and 3rd gear. Didn't take it up into 4th on the drive around the block. Letting off the gas after coming offload, I would hear the "thunk", no louder than before. "bag of marbles" also apparent when coming to a complete stop.
Double checked, no pink milkshake under radiator cap.
Next steps: I plan to drop the transmission pan and check for metal--I'm pretty sure this is unnecessary, but maybe it will buy me a few more weeks of carefree driving?--I am lucky that I have a v8 4Runner as a backup, so I can park this 3rd gen until I find a transmission to swap in. I know the 2001-2002 auto's are not directly compatible, are same year tacoma transmissions compatible? I expect it to be extremely difficult to find a transmission that is lower miles, so I'm thinking the most cost-effective manner is to locate the lowest mileage or currently running transmission, and just swap it in with all new fluids.
Might drive it to a few local (10 minute drive) transmission places to get their opinion after test driving, but I'm sure the rebuilds will be just as expensive as a donor transmission, if not more. The only reason why I would think of a rebuild is that this transmission has 120k miles.
Penny for your thoughts?
