Reasoning about Automatic Transmission issues (P0770)

[aawolf]

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.

--

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.

--

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?

 

[cashmoney]

Can't beat a manual for reliability.

 

[LookAtThatDog]

You probly came across some of my posts about P0770. I'm pretty sure the issue was with my torque converter. It started with strange noises, then slow shifting from R to D, finally slipping and CEL for P0770. I probly reset the code every time I put gas in the truck. It comes on when you get above a certain mph, might have been 45 or 60 or something. If you're not doing the solenoids yourself, it might be more cost efficient to swap the trans for a junkyard one. I just swapped mine, $400 for trans, $700 for labor.

My problem was solved for a couple weeks by doing a trans flush. You can find details on the site. basically you disconnect the trans cooler lines from the radiator, and empty out the fluid that's in there. Start the truck, wait for it to pump out 1 quart, turn the truck off, put a fresh quart in, over and over. It cost me about $100 in synthetic ATF. I'd start with that, I'm sure it'll fix your problem temporarily at least. If it comes on again before your next oil change, then you gotta make some moves (new solenoids or trans swap).

 

[aawolf]

>You probly came across some of my posts about P0770. I'm pretty sure the issue was with my torque converter. It started with strange noises, then slow shifting from R to D, finally slipping and CEL for P0770.

Thanks for the response. Yes I did see your post. It's exactly because I'm not seeing any other transmission related symptoms that I'm hesitant to throw throw the baby out with the bath water, so to speak. Not sure if I'm delusional or not though, or just am not tuned in enough to notice lock-up issues. Could someone describe what I'd be looking for if TCC was failing to lock/unlock in a timely way?

 

[LittleCaesar]

Replacement solenoids can be had in a kit for as low as $60. After dropping the pan and such along with some new ATF you are lighter in the wallet for less than $100 and your time. I'd try that first.

If the TC is on its way out you may find pieces of metal on the magnets in the pan and in the fluid.

 

[aawolf]

Replacement solenoids can be had in a kit for as low as $60. After dropping the pan and such along with some new ATF you are lighter in the wallet for less than $100 and your time. I'd try that first.

Any idea which kit? I've tried searching for OEM parts but had no luck.

If the TC is on its way out you may find pieces of metal on the magnets in the pan and in the fluid.

I did find some metal shavings, so it's a possibility.

 

[LittleCaesar]

As much as I hate to say use generic parts here I would. If you went with Denso OEM the cost would be over $400 for three. Others have used the kit inn the past with no problems if memory serves me correctly. But given where you want to go in the future with the 4runner you may want to find a reputable tranny shop.

What I would do stat is to install a Magnefine filter to catch as many shavings in the fluid before they reach the valve body.

 

[LookAtThatDog]

My vote is for fluid flush. I can almost promise it will solve your problems, at least temporarily. If symptoms come back, you have a different issue. If you want to do the solenoids, I'd recommend doing the flush at the same time.

 

[aawolf]

My vote is for fluid flush. I can almost promise it will solve your problems, at least temporarily. If symptoms come back, you have a different issue. If you want to do the solenoids, I'd recommend doing the flush at the same time.

Thanks. Not sure if you caught it in my orginal post but I've already done a full flush. So I guess I'm in the "you have a different issue" category. :/

 

[aawolf]

As much as I hate to say use generic parts here I would. If you went with Denso OEM the cost would be over $400 for three. Others have used the kit inn the past with no problems if memory serves me correctly. But given where you want to go in the future with the 4runner you may want to find a reputable tranny shop.

What I would do stat is to install a Magnefine filter to catch as many shavings in the fluid before they reach the valve body.

Thanks, I'll look into the Magnefine filter.

Any hints on who makes the solenoid kit / what to search for?

Yah you're probably right that I need to just take it in to a transmission specialist. I'm just hung up on the fact that it's running so well despite the CEL.

 

[MStudt]

Thanks. Not sure if you caught it in my orginal post but I've already done a full flush. So I guess I'm in the "you have a different issue" category. :/

If you've flushed it once already then doing another flush will do you zero good! I had the exact same code about 2 weeks ago. I then lost 4th gear, had slipping in 1st gear, and had slow shifts between 2nd and 3rd. Mine started from a pink milkshake last year. Shift solenoid E is an electrical issue with the solenoid. There are only 2 things that cause this code to come on. One being the solenoid is stuck open/closed, or a bad torque converter. Seeing how you have metal shavings in the fluid that doesn't point to the solenoid.

You can test the solenoid to make sure it's good. You can apply voltage to the solenoid, and see if it clicks. If it clicks then it's working fine, and your torque converter is bad. A bad torque converter would give you a clunky sound when braking/accelerating.

 

[LookAtThatDog]

Thanks. Not sure if you caught it in my orginal post but I've already done a full flush. So I guess I'm in the "you have a different issue" category. :/

I guess I can't read so good. :ybrick:

 

[LittleCaesar]

This is a read for ya, but gives some good information:
A340 Transmission issues and FAQs - Pirate4x4.Com : 4x4 and Off-Road Forum

 

[WRWhit93]

Sorry to resurrect this thread, but it's my turn. I got the p0770 code on my '00 4Runner I picked up about 1k miles ago (161k total now). came on on a long-ish road trip (500 miles) shortly after purchase. Changed the oil and got new tires since the PO didn't treat her too well and neglected some maintenance things. The code turned off afterwards with no reset. Didn't think all too much of it mostly due to not wanting to deal with the p0770 code and she drives fine.

Took her into my transmission guy to check everything out since there is no metal in the pan and it doesn't slip gears at all. He checked the solenoid itself, and drove it around on the highway, but couldn't recreate the code.

So here's where I sit now, torque converter not ruled out completely, but unlikely since no apparent issues with shifting or slipping or metal shavings in pan. Possible wearing down of the valve body housing causing loss of pressure at higher temps.

Thoughts? Would a transmission cooler help? Don't want to install one if the tranny's about to die soon. Or try to salvage one from a crap yard and replace the whole thing now?

Thanks in advance, guys!

 

[Rock_Rat]

I've been resetting a 0770 code since 2011 without any problems. (knock on wood) It's Solenoid E and tied to your overdrive. If you deselect your OD button, (turn your OD off) it shouldn't come on. My transmission shifts great in all gears and is not sluggish. Noticeable difference going up hill with added weight and 33's but that's all about the gearing.

No metal shavings, always do a drain and fill every time I do my oil change.

I'm holding off on doing any maintenance until I do the Import Performance Transmissions (IPT) Valve Body Upgrade before I install my SC.

 

[WRWhit93]

Thanks, I've reset it twice now. The problem is that I need emissions checks due to living in NoVA and you can't pass emissions with the code. Forgot to mention that. I think I'll just register my car down at school, haha. Get away from emissions.

 

[StreetCreeper]

I'm holding off on doing any maintenance until I do the Import Performance Transmissions (IPT) Valve Body Upgrade before I install my SC.

What's the dealy-O with this? New aftermarket valve body or do you send yours in to be upgraded? I'm guessing this is something like an old shift kit for firm quicker shifts? Price? And is this a supercharger thing or would it benefit us lesser mortals with regular stock engines?

 

[StreetCreeper]

Sorry to resurrect this thread, but it's my turn. I got the p0770 code on my '00 4Runner I picked up about 1k miles ago (161k total now). came on on a long-ish road trip (500 miles) shortly after purchase. Changed the oil and got new tires since the PO didn't treat her too well and neglected some maintenance things. The code turned off afterwards with no reset. Didn't think all too much of it mostly due to not wanting to deal with the p0770 code and she drives fine.

Took her into my transmission guy to check everything out since there is no metal in the pan and it doesn't slip gears at all. He checked the solenoid itself, and drove it around on the highway, but couldn't recreate the code.

So here's where I sit now, torque converter not ruled out completely, but unlikely since no apparent issues with shifting or slipping or metal shavings in pan. Possible wearing down of the valve body housing causing loss of pressure at higher temps.

Thoughts? Would a transmission cooler help? Don't want to install one if the tranny's about to die soon. Or try to salvage one from a crap yard and replace the whole thing now?

Thanks in advance, guys!

First I'm not a mechanic so don't listen to anything I say.

Second, since the code went away in its own, I don't think the ECU is detecting a problem anymore when it shifts. So maybe a random piece of crap in the solenoid that has now passed caused a code to be thrown.

Third, since the mechanic said the solenoids tested ok and there is no indication of big metal slivers or other carnage in your pan or on the magnets (I'll assume the mechanic at least eye-balled the metal filter/strainer and saw nothing alarming) I doubt your transmission is about to explode.

Fourth, you haven't noticed any difference in performance and no strange clunks or noises — so from what I've read it doesn't sound like a dying tourqe converter either (not yet anyway).

My 100% unprofessional guess is that it was just a fluke and not something to freak out on. If it reoccurs then take it more serious. Pay attention to how it shifts and note any differences you may find.

If you're really paranoid, perhaps a drain and fill or a gentle flush and then install a magnetic inline filter to help catch anything that might be floating around.

I speak not as someone who knows this stuff, but rather as someone who has been researching this stuff because I too get the P0770 and 0773 codes. In my case it's the lockup solenoid and it screws with the tourqe converter. The day after Christmas I'll be swapping out all three solenoids and flushing the old fluid out in hopes of a simple fix.

 

[Rock_Rat]

What's the dealy-O with this? New aftermarket valve body or do you send yours in to be upgraded? I'm guessing this is something like an old shift kit for firm quicker shifts? Price? And is this a supercharger thing or would it benefit us lesser mortals with regular stock engines?

The guys with the SC's can chime in here, but from all of the reading I've been doing it's primarily for the additional HP from the SC. The additional torque and HP on the transmission from a stand still, such as from a stop sign is too much for the A0340. It's fine if you only use the SC while "rolling" so to speak. I'm pretty sure the upgrade would be negligible without the SC. As for cost - ouch. I'm guessing it's around $450 and up shipped. I would take mine off and send it to them for the upgrade. The sad thing is I have an SC in my garage (almost a year now) I picked up for $700 with a new nose cone and all the goodies but won't install it until I've completed the "foundation work" first.

 

[tx_shooter]

Commenting so as to find this later - I have been chasing/ troubleshooting this code since I bought my '01 4R a few months ago. The PO had the solenoid replaced at a dealership a few months prior to selling the 4Runner. Now I am thinking about installing the Transgo shift kit to firm up the shifting - hoping that resolves the code. Yes - it is supercharged.

The Transgo kit is $100 + filter/gaskets and able to be installed ~4 hours.