I have an 89 Toyota p/u 4wd with an auto tranny. Doesn't "slip" in any gear, but recently it's been not wanting to shift down on deceleration. Doesn't do it all the time. Doesn't seem to make a difference being warmed up or cold. I don't know anything about auto's except where to add fluid and swapping one for another, but don't really wanna do that! I'm pretty well convinced it's an electrical problem, as from what I understand, they use solenoids for shifting-changing settings on the tranny. If when it does not shift down, I pull it manually down into low, it seems to go, again with no slippage that I can detect. Thought about doing the filter change, but a mechanic friend told me they don't use a filter? A modulator was also mentioned, but again, I'm totally in the dark where auto's are concerned. Since it's not slipping and seems to function properly when shifted manually, I'm thinking it can't be something real serious and should be within my means to correct, once the problem is identified. Another "symptom" I've noticed is that when it doesn't want to shift down, the little light on the dash that indicates if the O/D is on or not flashes dimly, when operating "normally", it does not flash and stays fully lit if you switch the O/D off. Don't know if that's a clue or not, but I would think it is related somehow. Since there seems to be somebody on this board that knows something about just about anything concerning just about any kind of vehicle, thought I'd put this out there before going to the Toyota forums or anywhere else. Any help-info-advice is greatly appreciated. I just need to know where to start looking, before I put any money in!

Thanks for looking and HAGO!

That's not an electronic trans. It ether has a detent cable or a vacuum modulator. Most likely the modulator is leaking atf. pull the hose off and you should see red, or brown, hopefully not black. When you down shift with the shifter your using the manual shift Spool valve that sends fluid pressure to the next lower clutch pac. The O/D is the locking converter clutch, if it stays locked it will kill the engine comming to a stop like a manual trans so I don't think that is it just that wnen you change throttle position the clutch should disengage.

[This message has been edited by Kekipi (edited 11-20-2010).]

I'll check the modulator hose. Thanks for your response. I've had Mitsubishi's before and they had solenoids that did about everything. The O/D is activated on the gearshift lever via a button, so it's got to be some kind of electrical switch, just not sure what the switch activates! There is also an O/D "override" switch on the console behind the gearshift lever, why they use two seperate switches to do the same thing (override the O/D-turn the O/D off) is beyond me, but as I said, I know nothing about auto trannys.

+ 2U!

HAGO!

Auto trans have gotten real complicated since computers are running them.
I dont know jack about them any more.

Last I heard some of them don't even have a dip stick . Its a sealed unit.
Heaven forbid if you had a slow leak and no way to check the level, let alone adding fluid.
Is somebody already thinking how much to add????

Spoon

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Two yeast spent their entire life "about 2 days" discussing what the purpose of life could be and not once did they even come close to the fact that they were making champagne. Quoted by: Unknown

Yea, I agree, they are great when they work! Kinda like an MGB...............

I don't think this one's quite that bad, as it does have a dipstick and as was pointed out above, this being an 89, is not an electronic tranny. I crawled under there and could not immediately identify the modulator.....granted it was getting dark, and I didn't spend allot of time looking, but nothing I saw looked like any modulators, I've seen before, and yes, I have changed them before, primarily on a 75 Camaro I used to have, but I do know what a modulator USED to look like can anybody give me a clue what this one might look like and where it might be located? I'm sure I'll find it, after all, there is a HOSE hooked up to it!, but just asking for further guidance to maybe make the job a little easier? The section on automatic transmissions in the manual I have (Haynes) says to refer servicing to a quilified technician...........humphhhhh so, there ya go, they don't want you in there! In my case I guess I can understand that attitude, or else why would I be on here asking for help, right?


HAGO!

[This message has been edited by Sage (edited 11-21-2010).]

The Chevy Malibu with the 3.1 has a tranny with no dip stick. to check and fill you lift the car level, with engine running and in park remove the plug and fill untill it spills out. Put back the threaded plug and good to go.

quote Originally posted by Spoon: Heaven forbid if you had a slow leak and no way to check the level, let alone adding fluid. Is somebody already thinking how much to add????

We the low-paid wrenchers are thinking about it..........the hi-paid geniuses in white shirts didnt...but then the seals they designs dont leak, and gears dont wear--according to them

(You have no IDEA how many screaming matches I have had in the past with ingunneeeers who will fight, argue, and kill that a certain part cant break a certain way.....yeh, well I am standin with one in my hand. I'll fed-ex it a-wipe and tell me again how it wont break there....

If engineers had to FIX even 1/3 of some of the stuff they designed it'd be "back to the drawing board"!!! Then like some doctors, they don't talk to each other, and don't consider each other's designs, so when the final product actually gets assembled, well.............you guys know what happens. You have to take half the car apart to replace a "non-failing" 79cent seal!

HAGO!

[This message has been edited by Sage (edited 11-20-2010).]

quote Originally posted by Sage: If engineers had to FIX even 1/3 of some of the stuff they designed it'd be "back to the drawing board"!!! Then like some doctors, they don't talk to each other, and don't consider each other's designs, so when the final product actually gets assembled, well.............you guys know what happens. You have to take half the car apart to replace a "non-failing" 79cent seal! HAGO!

Then the customer is bitchin about a $2500 labor bill for a 25-cent part.

quote Originally posted by Sage: Another "symptom" I've noticed is that when it doesn't want to shift down, the little light on the dash that indicates if the O/D is on or not flashes dimly, when operating "normally", it does not flash and stays fully lit if you switch the O/D off.

I don't know what tranny you have in your pickup, but my '86 Supra has the A340E; and my tranny IS ELECTRONICALLY CONTROLLED. I suspect that yours is as well. When the transmission computer notices a fault, it flashes the O/D light to let you know that there is a code set. (Very similar to a check engine light). Of course, turning off the O/D stops the light from flashing, as it is warning you that you are no longer in O/D.

I don't know if this will help you at all, since I'm not sure if you have the A340E in your pickup; but here's a link to the "Toyota Service Repair Manual" for the Supra, and the relevant diagnostic procedures for pulling/checking the codes from the A340E transmission.

http://www.cygnusx1.net/Sup...manual.aspx?S=AT&P=1

Hope that helps, or at least steers you in the right direction.

Ok, now we're gettin somewhere! That's exactly what I was looking for. Given all the symptoms and a "little" prior experience driving electronically controlled tranny vehicles, I kinda guessed there was some electrical connection to the situation. I'll study that site and see if I can at least determine where to start looking. The description in the troubleshooting section, which I just quickly looked over, describes my problem to a "T". Thanks for the info, don't know that it won't still end up in the hands of somebody with vast experience with these things, but at least I'll be armed with a little more knowledge. +2U

HAGO!

I just hope your truck and my Supra are close enough that the diagnostic procedures will be the same. If they are, the page that shows you how to check the codes in the transmission computer is page AT-13. Page AT-15 shows what the codes are, and what they mean. I just hope your diagnostic box and my diagnostic box are wired up the same; otherwise, you'll have to figure out which two terminals you'll have to jump in order to get the transmission into diagnostic mode.

Given your symptoms, I'd bet that the problem narrows down to one of the solenoids. If it is one of the solenoids (and your pickup has the A340E), here's a link with pics of taking the pan down; and it shows where the solenoids are. (Don't pay attention to anything after that, as they also go into shimming the accumulators-that are actuated by the solenoids-to help the tranny cope with the power that we abuse them with). Of course, the earlier link I provides is the service manual, and it has step by step instructions for replacing the solenoids. It's just nice to have pics of these things sometimes, which is why I provided the other link.

[This message has been edited by Deabionni (edited 11-21-2010).]