A340e gearbox gear change problem in first

[petergoudie]

A few weeks ago I posted a question regarding the A340e gearbox in my MX83 Cressdia. It was not picking up first gear and had a fault code of 62.

It was a faulty 1-2 change solenoid (which turned out to be a dry solder joint on the solenoid body). With the assistance of the forum members I located a set of Rostra (USA) solenoids and fitted them to the gearbox. I used Valvoline Type D auto transmission fluid which is what Valvoline recommend and is most likely the same as Dextron 2 or possibly 3.

The gearbox now picks up all gears except when the engine is cold, it stays in first. It won't change up into second unless you try to back off quickly or wait for say a minute of driving in first; or stop and start once or twice.

I just checked the computer and there are no fault codes. After I changed the solenoids I back probed the computer connector and all three solenoids showed a low resistance as they are supposed to.

The only difference was the non-genuine solenoids were a little lower resistance. Toyota spec says 11 to 15 ohms. The Toyota solenoid was about 13 ohm. The Rostra non-genuine was about 9 ohm. However, at such low resistances a standard multi-meter is never accurate although I doubt if it should make any difference as when the gearbox is operating it works quite OK.

On the basis there are no fault codes showing and I have the throttle cable adjusted correctly (0 to 1 mm) can anyone advise what might be the problem now? Does the computer use one of the engine temperature sensors to control the gearchange at low temps?

A thought I have is that with the help of MOS (toymod admin) I changed the plastic cover on the wiring loom spade connector for solenoid 2-3 (part of it had broken). At the beginning it was hard to release the cover until I worked out how it was held in. I'm wondering if I have opened up the spade a little and have reduced its contact force (although the resistance is OK at the computer). As I understand it, to select second gear both solenoids 1-2 & 2-3 have to be on. So if it's not selecting second (irresepective that the problem seems only to be at start off when cold) solenoid 2-3 might be the culpret except the computer shows no fault codes.

Has anyone have any ideas of what the problem is?

[PlacentaJuan]

if it only happens when cold could it be the gearbox temp sensor?

on the fluid oulet (to the cooler) there is a temp sensor that wont let overdrive kick in until the fluid is warm or something. i dont know if this would keep it in first gear though, but maybe you could try diconnecting it and seeing if there is any difference.

otherwise it could be your spade problem that closed up slightly once it expands from the heat, and the copmuter might not show a fault if the problem is only slightly intermittent.

[petergoudie]

Thanks. I spent a bit of time searching the internet and found a 2006 thread from a person in the US. He owned another toyota with A340e gearbox and 90,000k on the clock with a similar fault that took about a year to diagnose. He said it was some dirt in the valve body in the 1-2 change area. I hope this isn't my case as I don't want to drop the oil pan again and waste the new oil, gasket & filter (as I only did it 3 days ago). In addition, I haven't found any info on how to split and repair the valve body plus I guess there is some expensive kit I have to buy.

[Mos]

if it only happens when cold could it be the gearbox temp sensor?

It doesn't have one...

otherwise it could be your spade problem that closed up slightly once it expands from the heat, and the copmuter might not show a fault if the problem is only slightly intermittent.

I doubt it's that. These solenoids use bugger all current - under 1.5A - the plug would have to be very percievably loose before it gave any problems.

As I understand it, to select second gear both solenoids 1-2 & 2-3 have to be on. So if it's not selecting second (irresepective that the problem seems only to be at start off when cold) solenoid 2-3 might be the culpret except the computer shows no fault codes.

You would need to try to isolate the problem. You can observe the voltages on the S1, S2 pins on the ECU. This would tell you if the computer is wanting to switch solenoids - it should be - or if it's something further down the line.
If the computer is trying to operate that solenoid but the auto is not changing gears you could measure and observe the current through the solenoid - this will tell you if the solenoid is energising.

I can't think of an easy was of telling if the solenoid has operated once energised; I would tend to think that if the solenoid is pulling current it's a hydraulic problem, but it could be the solenoid not switching (maybe).

I would expect that the computer is trying to switch it and that the problem is hydraulic - the first part is relatively easy to confirm/diagnose. My initial thought was fluid type, but then again I've used non-genuine fluid without a problem (but the low cost of the genuine fluid leaves little reason to use non-genuine).
In terms of transmission management, to my knowledge there is nothing temperature related that would prevent a 1-2 shift; some boxes won't shift into over drive until certain temperature conditions are met, but 1-2 always happens - probing of S1 and S2 should settle this though.

Mos.

[petergoudie]

I'll post a more comphrensive reply later as I have to go out this evening.

Note that the gearbox was functioning OK before the 1-2 solenoid failure.

I replaced the solenoid and the gearbox continues to act quite normal except for the first 100 to 200 metres at start off when the engine is cold.

I also replaced the oil.

I left the gearbox drain for a day or two and at the refill it took 3 litres whereas the handbook says a refill is 1.6 litres. Over that day ot two it kept slowly dripping hence the 3 litres. This is what makes me think I might have dislodged some build up of something from the gearbox into the valve body.

I'll think of a way to check that the 2-3 solenoid is being fired at the change point when cold. I might put a needle through the solenoid wire in the engine bay and then to a multimeter inside the car when I drive it.

[cambelt]

Some of the cressida trannys did this , too heavy atf does it . if you drop the valve body down you can take the 1/2 shift valve out and give it a bit of a emery with 600 paper . solves the problem.
Dave

[petergoudie]

Cambelt Dave, it appears that you've experienced the same problem. Is this so and did the emery fix it?

Dave, Mos & PlacentaJuan - I just spoke to Valvoline technical - it was quite intersting. They too agreed that it might be a viscosity issue. I was not aware that ATF viscosity could change so much with temperature. The guy said that at 90 degrees centigrade (operating temp) the ATF might be 10 grade. When cold it might be as high as 150. He said that at lower temps the viscosity can double every 10 degrees.

He said that Dextron 3 (Valvoline equivalent ATF DX-3) would be thinner because it uses friction modifiers. The first gear sticking problem might be overcome but in some gearboxes the DX3 friction modifiers can cause the gearbox to hunt at idle.

The Toyota T3 ATF is equivalent to Dex3 and the Toyota T4 oil is a semi-synthetic of Dex3 quality or better. The valvoline full synthetic which is supposed to be best is Maxlife Auto Transmission Fluid.

The tech guy suggested to drain and refill again using my spare oil as I don't know what was in there before. If that does not fix the problem try a Dex3 equivalent or go to the synthetic (if I can afford it).

Do anyone have any other thoughts on this approach?

[oldcorollas]

get a big clean pan, and clean the outside of gearbox before dropping oil... so you can use it again if necessary

check the leccy problems first (you can probably trace the wires back up from the gearbox, to a plug, where it is easier to stick in the multimeter probes.. and possibly within the cabin. if it is electrical problem, no oil will fix it.

if it is a dirt/sticking problem of the solenoid, oil will probably not fix it.

but if it is just a viscosity issue, then oil might fix it

do you let car warm up before driving? if you just cruise the first 100-200m in first, it always chages up?

[AndrewJZX100]

I got this issue too when my cress was running. Would refuse to do any gear changing whilst cold. Usually I could help it along by moving the stick from N to 1 a few times whilst rolling slowly down my street, then driving off in 1st, flicking to N and backing off till it got back to idle, then put it in 2 and *most* of the time it'd shift to 2nd and it'd be right from then on.

[petergoudie]

Old Corolla's & Andrew. Yes it only locks up at cold when starting. Note from my comments above it only did this after I changed the oil and solenoid. On the basis it works fine after it makes that first gearchange into second it is more likely an oil issue (as the solenoids must be working at least from that time). The Valvoline tech guy also thought the oil might be the problem - he made no effort to defend the type of oil that was in their recommended sheets.

I'm thinking of pouring in one of those additives that's supposed to do everything to improve the gearbox. Has anyone ever tried this?

One other thing I might do is to idle the car from cold for say 15 minutes in the hope that some of the engine heat will be transferred to the gearbox. I'll then drive it and see what happens although if the 1-2 shuttle valve is stuck it will probably need the first burst of oil pressure to move it.

[Z2TT]

Would the amount of oil in your transmission be causing a problem? maybe it is underfilled.

[Kroozerdave]

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Do anyone have any other thoughts on this approach?

I ended up with some of the lower spec valveoline via parts guy.

Had a bit of a cold snap, my problem was when cold seemed to act like something was locked/sticking took a lot more revs for first 100-200 yards then was ok. Manually selecting 1st then changing to second seemed to help to drive at least. I was thinking I must have broken something that was going to be expensive to fix.
Even then it was brilliant once warmed up a bit smooth changes, plenty of torque, OD working nicely.

From marks on lawn noticed probably have a small leak as well. Other comments in threads noted even small difference if fluid level made big difference to working. Checking when hot on dipstick showed needed fluid (much larger difference between cold level and hot than I've noticed on other autos I've had) so I made sure got better grade, different brand for top-up all seems right again.

Your earlier comments from tech reinforced my wider net searches that auto fluids probably differ more than previously these days. That now electronics, servos, clutch packs with various material spacers and old favourite internal valves, autos are a bit more complex and vehicle specific than the old 2 speed autos of last century. Good news is when working well they do a lot more as well.

[Z2TT]

I use Valvoline Dexrom III, which is backward compatible with Dexron II, isn't Dexron II the type of ATF that is specified for the A340E ?

[petergoudie]

Yes Dex 3 is backwards compatible. I drained out the Dex 2 (Valvolive Type D) today and replaced with Dex 3 as per my messages above. I plan to do this three times as the drain is only about a quarter of the what's hiding elsewhere in the gearbox.

(Dextron is a registered trade mark of General Motors that's why other manufacturers call their oil type D or Dex-3 or DX3 or ATF111 or ATF3)