03 V8: Transmission lets go, slams back into gear

[Montego Murph]

I'm having a hard time verbalizing this one...

Engine is at operating temperature, 40* outside.
What I'm trying to describe happens if I accelerate after coming almost to a stop from a cruising speed, then accelerating again, like a 'rolling stop' at an intersection or when someone in front of me slows to a snail's pace to make their right turn.

Actual speed is unknown, but it's around the 1-2 shift threshold.

While I start to accelerate, it goes into a "neutral" state for a split-second and the engine revs, then suddenly slams into 2nd. It's almost as if I moved the gearshift from Drive to Neutral for a split second with my foot lightly on the gas.

Now, I have noticed this over the years on a much milder scale. Like if I'm coasting and then hit the gas, it's a hard engagement which reminds me of the old centrifugal clutches that go-carts used to have. Annoying, but something I learned to live with and adapted my pedal foot. This is a really hard "ooh, I wonder if I broke something" feeling, like popping a clutch or doing a neutral drop.

Anyone familiar with this? Suggestions or ideas?

 

[Sarge]

Probably just an accumulation of sludge. Have you ever done a flush/fill?

Sarge

 

[waypoint]

Sounds like it's low on transmission fluid. Check the dipstick level with the engine running, transmission at operating temp. Report your findings.

 

[lj4r]

Drain and flush a couple of times. Use Toyota trans fluid. Good luck. Phil

 

[Montego Murph]

Ok. I have information.

While running errands earlier it did this three times. However today I noticed that while slowing down prior to the slip, i got a "clunk" similar to the driveshaft clunk, but heavier. Then I would get the slip between 1 and 2 when taking off from the stop.

After driving 15-20 min I checked the fluid. It comes to the bottom of "low" on the hot side of the stick. So it is a little low but it strikes me as odd I would have issues this severe with only a quart low. (Although i do need to find out what quantity the difference between high and low represents.)

As for the maintenance question, in September I did do a fluid exchange (via transmission cooler) with Valvoline Maxlife, and was incredibly meticulous about matching what came out with what went in, then checked it a few times over the next week and all was well. I've driven a few thousand miles since then and zero issues until the other day.

(I typed this part while waiting for something... now I'm home)

On the way home from part one of this message, it did this "slip" thing repeatedly, and I got a check engine light, along with the VSC/TRAC combo.

Here are the codes I got:
P0771 - Shift Solenoid E Performance or Stuck Off (confirmed)
P0771 - Shift Solenoid E Performance or Stuck Off (current)

C1201 - Engine Control System Malfunction (current)
(I understand this is simply a generic "something is wrong" code and not something directly related)

B2799 - Engine Immobilzer System (history)
(A while back I did try to start it with my "door only" metal emergency key so this might be that)

I'm going to do a little searching and see what I can find. Meanwhile... anyone dealt with this before?
One of the thoughts going through my head is "Did the solenoid just fail, or did something cause it to fail?"


I thought this was interesting... but odd that it's not mentioned anywhere on any forum so I'm going to bet it's not extremely accurate. SOMEONE would have seen this by now:
SOLVED: 03 Toyota 4runner 4wd 4.7l had codes p0771 , - Fixya
Hello.
Before you start looking at replacing solenoids, here is something that you need to know:
Toyota has a technical service bulletin regarding this issue.
Changing the solenoids will NOT rectify your situation. Replacing the ECU in the car is what you need to do. The logic/programming is the problem, not the solenoids.
The good news is this: The ECU is covered, under the factory warranty! It will be replaced for free, if your car has less than 80,000 miles on it.
If you have more miles than 80K, call the Toyota Customer Experience Center at 800-331-4331; an analyst may be able to help offset your costs; they do this quite frequently.
This should get you fixed up. Thanks for visiting FixYa!


Tomorrow when it's light out, I'm going to correct the the fluid level and see if that solves it. If not, move on to more serious ideas...

 

[waypoint]

After driving 15-20 min I checked the fluid. It comes to the bottom of "low" on the hot side of the stick. So it is a little low but it strikes me as odd I would have issues this severe with only a quart low. (Although i do need to find out what quantity the difference between high and low represents.)

Typically it's 1 quart from low to full on transmission dipsticks, but add fluid incrementally and stop just short of the full mark...allowing time for the new cold fluid to get up to temp before re-checking.

You're on the right path addressing the simple thing first via fluid level, while researching the total problem. If you're really 1 quart low, that's 25% of the pan capacity and could be enough to cause the pickup to draw air under the right conditions e.g. acceleration sloshing the fluid away from the pickup.

If fluid level correction doesn't fix it and you go the ECM replacement route, a junkyard unit should be a partial DIY job assuming you have the master key(s). There's a procedure for most Toyota vehicles with anti-theft systems, series of steps and a ~30 minute wait. You may need a shop tool to write your VIN to the new ECM, some locksmiths can do this cheaper than the dealership.

Keep us posted.

 

[Montego Murph]

Doing a little research this morning before checking the fluid.

Toyota dealer says that based on what I see, I should add a half quart. However, he doesn't think that's low enough to cause those issues. Still gonna try it.

I found this PDF called AT-87 which I have attached. (probably page 87 of the AT section of the shop manual) that discusses the P0771 code. (My code read Shift Solenoid E Performance or Stuck Off)

Oddly enough, this document states the opposite of the situation I am experiencing:
Stuck On: ECM directs the gearshift to switch to 2nd gear, clutch slips.
Stuck Off: ECM directs the gearshift to switch to 5th gear, goes to 4th


I cannot find any mention of a TSB related to the "fixya" post I mentioned earlier. I'm not ruling anything out at this point, but with no evidence...

 

[anonymousgromers]

I had something very similar where it felt like someone rear ended me and would not shift gears like it wouldn't catch it would then rev real high to red line.

after having it sat for like 4 months at a mechanic shop he pulled solenoid problems like you and advised me to purchase a new computer for $1200 cdn which I still think was not the problem

it ended up being a wiring harness that was tore but he never said where, that fixed the problem for me. So I'd say to take a look at all your wiring harnesses and see if that's the problem.


2004 toyota 4Runner limited 4WD 4.7L V8 | Gibson cat back exhaust

 

[MikeinNH67]

Check out the video below to see if it pertains to yours. Seems the pins can break off on the harness that goes into the tranny which makes you think it's going bad but it really can't control the solenoids properly.

YouTube

 

[Montego Murph]

I hope it's not that pin issue... That looks miserable, and I'd really rather someone did not carve a hole into my floor!

I mulled this over and seeing as I lack experience, tine, knowledge, and a garage to work in, I'm going to have it towed to a local transmission shop that I've heard good things about.

I'll post my results up here when I know something.

And then I gotta get my timing belt done PRONTO. I'm on borrowed time for that one....

 

[anonymousgromers]

I hope it's not that pin issue... That looks miserable, and I'd really rather someone did not carve a hole into my floor!



I mulled this over and seeing as I lack experience, tine, knowledge, and a garage to work in, I'm going to have it towed to a local transmission shop that I've heard good things about.



I'll post my results up here when I know something.



And then I gotta get my timing belt done PRONTO. I'm on borrowed time for that one....

Good luck man hope its not anything to serious or expensive I know how much of a pain in the ass it can be having a problem like that and not knowing what it could be, also I'm on the same boat as you in terms of the timing belt, 180k on the original timing belt shes been sitting in my garage for the past few days waiting for the belt kit to come in the mail haha.

 

[Montego Murph]

Update:

Just got a call from the transmission shop. He walked me through the whole process of everything he did. He said that mechanically the transmission is fine, this is an electrical issue, and made a reference to the wiring harness corrosion suggested above.

He suggested having it towed to the dealer where they can do a full diagnosis with Toyota-specific equipment. I'm having that done so if nothing else I can know exactly what is wrong with it and then decide how to proceed. I suspect they are going to pull something like "need to replace entire vehicle wiring harness $5000."

Transmission shop says that if it is the harness, it can be repaired with the transmission in the vehicle. That's outside of my realm of ability right now so I'm going to end up paying someone to do it unfortunately.

Edit: It looks like there are two wiring harnesses that would need to be replaced. One from the engine ECM to the transmission, and then inside the transmission that connects the first harness to the valve body. Hopefully it's that straightforward.

 

[Keros]

Update:

Just got a call from the transmission shop. He walked me through the whole process of everything he did. He said that mechanically the transmission is fine, this is an electrical issue, and made a reference to the wiring harness corrosion suggested above.

He suggested having it towed to the dealer where they can do a full diagnosis with Toyota-specific equipment. I'm having that done so if nothing else I can know exactly what is wrong with it and then decide how to proceed. I suspect they are going to pull something like "need to replace entire vehicle wiring harness $5000."

Transmission shop says that if it is the harness, it can be repaired with the transmission in the vehicle. That's outside of my realm of ability right now so I'm going to end up paying someone to do it unfortunately.

Interesting... I've had this issue for years now, though my truck throws no codes at all (even during executing the problem, which I'm decent at replicating and avoiding now).

Regardless, I've acquired a new transmission as that most shops all agree it's a problem within the transmission. And that rebuilding it would cost a fortune.

Swapping out the trans is the next project; just stalled due to lack of funding.

 

[Montego Murph]

As expected, the dealer threw out a line of crap.

All the wiring is ok, we did a continuity test. (?)
The code we pulled said to replace a solenoid. The techs say that more often than not, we replace the solenoid, but then the issue comes back in 6 months. We have no idea what causes the issues, so we say it's best to just replace the transmission.
They have a good used transmission lined up for $606, and $920 labor
Or, I can buy a Remanufactured Toyota trans for $3,000

I asked him about replacing two wiring harnesses, ECM to Trans, and Trans to Valve body. He didn't have answers.

The next question was "Whatever this external force is that is going to cause the new solenoid to fail, wouldn't that also ruin the solenoids in the new transmission?" Now there's something suddenly mechanically wrong with my transmission causing it to fail. The independent shop said it's an electrical issue, and mechanically sound.

I give up.

 

[waypoint]

Did you ever top off your fluid?

Also...was it doing this before the flush & fill with Valvoline Maxlife fluid?

edit to add:
Here's what I'd do, they're all fairly low cost and difficulty:

1.) Top off trans fluid and re-test;
2.) Flush and fill with thicker T-IV spec fluid...see viscosity comparison below, significant difference;
3.) Junkyard ECU swap: car-part.com shows them averaging $75, get one with a part # last digit >0, this usually indicates updated firmware.

Maxlife: 5.91 cSt @ 100degC; 28.82 cSt @ 40degC
Castrol Transmax High Mileage: 8 cSt @ 100degF; 36.6 cSt @ 40degC
Castrol Import Multi Vehicle: same as Transmax High Mileage
Mobil 3309: 7.1 cSt @ 100degC; 33 cSt @ 40degC

 

[Montego Murph]

I did -- the fluid level was the first thing I checked. I added about 1/2 quart.

No -- the transmission was not doing this before the Maxlife swap a few months ago, the first time was Feb 16. The 1-2 shift is so violent that I wouldn't have driven it all this time. I won't even drive it now -- I'm having it towed to all these places. (Thankfully I have roadside assistance)

Educate me because I'm still learning about transmissions. Not questioning your knowledge because clearly you have more than I do: How will thicker fluid help this situation, and why do you think it is the ECM? If I pulled the ECM, would there be a visible signal (like a burned capacitor) or did it just "forget" how to work properly?

 

[waypoint]

I did -- the fluid level was the first thing I checked. I added about 1/2 quart.

No -- the transmission was not doing this before the Maxlife swap a few months ago, the first time was Feb 16. The 1-2 shift is so violent that I wouldn't have driven it all this time. I won't even drive it now -- I'm having it towed to all these places. (Thankfully I have roadside assistance)

Educate me because I'm still learning about transmissions. Not questioning your knowledge because clearly you have more than I do: How will thicker fluid help this situation, and why do you think it is the ECM? If I pulled the ECM, would there be a visible signal (like a burned capacitor) or did it just "forget" how to work properly?

I'm no transmission expert, what I laid out was a series of steps to rule out possible causes of the problem at low cost and difficulty.

Fluid: your transmission calls for T-IV fluid, not newer WS fluid which is lower viscosity. Auto transmissions operate on hydraulic pressure. Pressure is resistance to flow, and lower viscosity fluid offers less resistance to flow than higher viscosity fluid. Thinner fluid = lower pressure. Add in the fact that your problems started a while after the change to thinner Maxlife, and it's a possible cause.

ECM: the 'fixya' post you referenced earlier is my only indicator that this may be a possible cause. I have seen bizarre transmission problems caused by, and cured by, powertrain software in other vehicles.

 

[Sarge]

Well, aside from hacking a hole into the trans tunnel - this did get the problem solved.
YouTube

This is a problem that will become a lot more commonplace with these newer electronic control systems. Corrosion will catch up, eventually to all of these components. For anyone attempting to clean any of these pin type of connectors - look into Caig Industries De-Oxit cleaners for electronics. The normal electrical cleaners won't work very well, if at all on these pins - they are just too weak. The De-Oxit line will clean those pins and also protect them without damaging components. For really corroded parts - D-100 cleaner, followed by D-5 to finish cleaning and protect the pins against rotting again. Electrical cleaners such as CRC and others are just a washing agent, not a corrosion-eating cleaner. There is a huge difference - especially in electronic controls such as volume knobs, ect. These products were developed specifically to clean controls on stereo equipment and other such parts as well as board connectors without damaging components that are highly sensitive. After trying everything else, I've repaired a lot of equipment using DeOxit with a nearly perfect result every time. The other products that are on the market are a waste of time/money.

DeoxIT D-Series page with shop - CAIG

The other option is to drop the pan, pull that internal harness and replace it, along with the ECU harness. Not sure how involved that would become, but I suspect that harness could be above the valve body - which turns into a bigger job quickly. Wish we had a lift here and a shop that could handle having it apart for a few days - wouldn't mind taking a shot at it.

Sarge

 

[waypoint]

Well, aside from hacking a hole into the trans tunnel - this did get the problem solved.
YouTube

That's a very informative video for those of us that haven't hit this problem...yet. Ticking time bomb with corrosion and makes a strong argument to unplug the transmission connectors and protect the pins with appropriate corrosion inhibitor. The connectors are sprayed with water (and salt in many cases) such that even the seals can't prevent this outcome.

Spring maintenance project queued up! Thanks Sarge. Can of DeoxIT D5 ordered, and I'll apply my usual thin coat of dielectric grease along the weatherproof seal during reassembly.

 

[Sithrebel15]

Interesting. I've had that issues twice that I can recall both time getting onto a freeway. It's been a few years since it's happened though and the only ones I pulled are for another issue.