MTL_4runner

It is a bit of a daunting task to take it apart but many of the guys have sent their valve bodies out get modified so I would put it about midrange on the difficulty scale. Just be careful of where everything goes and you will be fine.

Funny you say PFK because before I moved here I had never heard of that.....KFC, YES.....PFK, NO....
I live right near wheer you used to live.....almost in NDG....nice area, I love it.

TechWrench

Ava, All; I found this site while searching for info on the A340H, which goes into a lot of detail on it and how it works. There is a very good section on the solenoid valves. Maybe it will help.

http://www.autoshop101.com/forms/h16.pdf

Good luck.

JD

Ava

I have just read this post and all the various comments.

One aspect you can discount are the standard electrical fault codes as unless your OD light started to blink while driving there are no faults in these areas. You have now confirmed this by getting a continuous blink via checking for these codes which means all is OK.

But my first question is.

Where is the oil level on your trans dipstick and what method do you normally use to check it?

JD

Babypig

quote "One aspect you can discount are the standard electrical fault codes as unless your OD light started to blink while driving there are no faults in these areas. You have now confirmed this by getting a continuous blink via checking for these codes which means all is OK. "

Except that by shifting the trans manually everything works fine which is a symptom of a faulty solenoid. It could even be grounding out due to a wire rubbed bare. The wiring isn't the best quality and I've had this happen to one of my injectors. They may only fault when hot, which mine did, causing the O/D light to flash sometimes but not others. But while you bring it up, Ava, how is the level of the fluid?

JD

No, shifting the trans successfully manually does not limit the problem to an electrical fault as the problem can still be hydraulic, such as a bad solenoid seal and a very possible likely cause to the problem.

The fault codes system is purely designed to pick up electrical gliches such as open circuits etc and the fact that Ava has indicated it hasn’t flashed etc then there are no “electrical” glitches in the monitored areas from stored codes.

But the problem can still be electrical, mechanical or hydraulic and some issues have been covered and some have not. The A340H is a hydraulically operated trans controlled by an ECU.

But despite the advice so far I will be surprised if the problem is simply nothing more than not enough trans fluid. A very cheap fix.

Ava

I check as follows: Start engine, go trough all positions of the shift handle, pausing at each position, read dipstick while the engine is still running.

Ava.

JD

Ava

Great and I assume this is after you have done a few miles and the engine and trans oil is hot etc.

JD

Ava

To put it another way: I've used a pan of 4.5 litres to drain the trans and it was filled to the very top. We can assume the dipstick belongs to the car.

I'm looking for 'place' in the trans that could be responsible for the absence of drive in *all* positions of the shiftlever(s).

When the car malfunctions I have *some* drive but not enough te move the car. This could be caused when there's a common ground wire for the two shift solenoids; then I would be trying to take of in overdrive. I don' know if the car would be able to to do that, and I think that would put a noticeable strain on the engine, which it really doesn't on mine.

I still have to check the trans tempsensor.

Ava.

TechWrench

AVA, I have not mentioned fluid level because I assumed this had already been checked. And I know the generally recomended procedure is to check the fluid after it has reached normal operating temperature. But I have checked the fluid level on hundreds of vehicles of all makes, and one thing I am sure of is that in the real world, the fluid temperature does not make enough difference in the reading you get on the dip stick to cause the type of problems you are having. As long as you run the trans trhough all the gears while at an idle, as the manual recommends, and then put it back into park before checking, while the engine is still idling while on level ground any reading you get should be fairly accurate. Now I am not suggesting that the recommended procedure is wrong, just that the difference between a reading with fluid that is 'cool' and a reading with fluid at normal operating temperature (hot) should not be that much different. Certainly not enough to cause an otherwise normal transmission to malfunction. One other thing I forgot to mention, in most cases if the fluid level is too low, in addition to a loss of pressure you will quite often hear a whine from the transmission pump caused by the pump gears running 'dry'. Of course, this pump whine can also be caused by a clogged filter starving the pump.

Babypig

I didn't actually say that shifting it manually is an electrical problem. Changing gears manually points to a hydraulic problem, i.e. the solenoids. I simply stated that there could be a ground and not allowing a solenoid to open. Being electrically controlled they are either open or closed. There is no inbetween. I agree that it is most likely a solenoid that is the problem, I believe the lock-up solenoid, as it won't go forward or reverse. It could even be the trans ECU is fried.

Ava, have you had any work done to the throttle body lately? In particular the TPS? Or to the speed sensors?

Ava

I've checked hot and cool. There is a substantial distance between the hot and cool marks on the dipstick, so there must be quite an expansion. Hmmm, why is that? Does oil expand that much? Foaming?

This whining happened to me when the filter was clogged, but I mistakenly subscribed it to the A/C compressor belt that had lost a part on the inside. I thought it was slipping sometimes, which it must have done since the belt showed signes of that.

Ava.

Ava

I think there *is* an inbetween. Duing the search for tranny info I found that there are socalled modulating solenoids which do more than open/close. But I don't think they're on my Aisin AW model 30-83LE.

I recently removed both heads to repair some leaks that were poorly mended by an previous owner. But I didn't change the trottle body, I think. I adjusted the TPS a while back when I found out it never 'saw' the idle status. Speed sensors I never touched.

Ava.

TechWrench

When you say " a substantial distance" how much in milimeters roughly, were the difference between the hot and cool readings
on the dip stick? For instance, I would guess that a difference of 10 mm ( 3/8") would equate to about a pint or less. As to why the difference, most of should be just the fluid expanding as it gets hot. If you were experiencing foaming, you should see it in small bubbles in the fluid on the stick. The most likely reasons for foaming, if it is happening are again, low fluid levels causing the pump to run dry and whip the fluid up while trying to pump it or some type of air leak in the passages from the filter to the pump allowing air to enter the pump with the fluid. Some early types of transmission filters had a tube extending up into the pump which carried the fluid from the filter to it. They were usually sealed with an o'ring, and if this o'ring was missing or damaged it would let air enter and cause foaming to occur. I don't think your unit uses this type of filter, but I am not sure. Do you remember how the filter connected to the valve body? Was there some type of gasket which sealed the filter to the oil pickup passage? This might be an area to look into.

JD

Ava

The first issue is to eliminate the obvious and the symptoms you first described are classic low oil level symptoms so IMHO this does need to be assessed and eliminated as the possible cause.

The A340H is very susceptible to oil levels.

The cool engine running level can only be used as a guide as it’s the hot level that counts. You need to do at least ½ hour drive and check it hot and the level must be on the hot line. But another quick indication is to check the level first thing in the morning without starting the engine, the oil level should be around 3/8-1/2” ABOVE the hot level. If it is then its probably OK when running hot, if not then you do need to check it properly.

Correct, the A340H has no modulating solenoids. These are used in the Supras and V8’s to smooth the shift.

Changing gears manually points to a hydraulic problem, i.e. the solenoids. I simply stated that there could be a ground and not allowing a solenoid to open.

Babypig, yep its pointing to a hydraulic problem, but not a bad solenoid ground etc as a fault code would have activated.

Being electrically controlled they are either open or closed. There is no inbetween. I agree that it is most likely a solenoid that is the problem, I believe the lock-up solenoid, as it won't go forward or reverse.

Actually, there can be an inbetween as the fault code system cannot determine whether a solenoid has fully activated. Therefore, it is possible that although it gets a perfect 12v feed it has not fully opened or closed thus affecting shift pressures or alternatively it could be purely mechanical as its seal could be buggered

No mate the lock up solenoid 3 has nothing to do with forward or reverse as it only controls torque converter lock up, but yes bad solenoids 1&2 are a definite possibility and their replacement might be well worth trying.

I recently removed both heads to repair some leaks that were poorly mended by an previous owner. But I didn't change the throttle body, I think. I adjusted the TPS a while back when I found out it never 'saw' the idle status. Speed sensors I never touched.

Ava, did you troubles start after you did this work or before.

Ava

I don't think that's true. My car in shift position '2' starts to drive in first and switches to second when it reaches a certain speed.

I think the position of the shiftlever chooses another shift program, not mechanically change the gears per sé. That would mean that the solenoids are probably still used for (at least some of) the shifting.

A.

Babypig

But in anything other than drive does it work okay? I'm just trying to tell you what in my experience the problem that i had, which is similar to yours, was. Take that for what it's worth. I'm not quoting stuff out of a manual, I'm going by what happened with my truck.

Good luck with it.

Ava

By substantial I mean four centimeters (40 mm or approx. 1,5 inches). That much is the difference between the hot and cool markings on the dipstick.

This morning I checked before I left and noticed the level was a little (4-5 mm) below the lowest cool markings. I had some Dextron III (about half a quart) left and put that in. About 10-15 minutes later the car failed on me when I wanted to pull away at a shop. I got it to go (revving in D and R caused it to mend its ways with a bang) and I could drive normally. Less than an hour later, same thing. Always after a stop.

I can't imagine I have too much oil, but if adding has this effect I'm starting to wonder. I think Toyota says it needs 4,5 litres, and that's excactly what was in the sump when I pulled the pan.

A while ago I had the transmission oil changed and arrived home with a dry dipstick, not having noticed any difference. The boy who filled the trans took a very long time to inspect the dipstick, called his superior and I still wound up adding a whole extra quart of DIII.

Ava.

Ava

I said something like "it won't go in *any* of the shift lever(s) positions". Just had it happen three times this morning, after topping it off with half a quart of DIII.

Ava.

JD

This morning I checked before I left and noticed the level was a little (4-5 mm) below the lowest cool markings.

This is important. Was this the level that resulted from checking as I mentioned with the motor not running?

About 10-15 minutes later the car failed on me when I wanted to pull away at a shop. I got it to go (revving in D and R caused it to mend its ways with a BANG and I could drive normally. Less than an hour later, same thing. Always after a stop.

Ava these are classic symtoms of not enough oil in the trans.

You need to do a positive level check and then get back to us with a yes or no whether the oil level is correct. Forget what came out of it or went back in.

Check it either in the morning on a flat surface before starting and the level should be 3/8-1/2" ABOVE the hot level or check it after 1/2 hour drive with the engine running and it should be on the hot level, preferably a fraction above.

If its low fill it to its correct level and then test and get back to us. Otherwise we are all chasing our tails until this is eliminated as the cause of your problems.

JD

Ava

I will check cold and not running and after a drive and hot, to be sure. Half an hour might not be neccessary since I live in the tropics where currently a 'cold' night is about 26.5 Celcius (80 Fahrenheit).

And the troubles came with the car, I'm just trying to undo years of bad (read: "no") maintenance.

The price was right, though. ;o)

A.