elnido

1995 T100 4x4 A/T 5vzfe 130,000mi.


My CEL came on again this week, twice in 3 days. I assume the codes are still PO773 and PO770 re: solenoid E.
About 4k after the dreaded Tranny Flush... the CEL came on and after much research, I had some BG tranny product poured in. Problem solved, no more CEL, except maybe once or twice in 3-4K miles. Now it seems to be rearing its ugly head again that my tranny ain't happy. It's been about 8K since the tranny flush. Truck seems to shift normal (slight observation of occasional wierd shift in O/D shift region.)

My questions are:
-Should I change tranny fluid again now?
-Should I just dump some MORE BG in with the idea that all the crap that may be swimming in the system might get broken down furthur? How much of this stuff can you use before you must change AT fluid?
-Should I drop the pan and clean the filter?

Any thoughts are appreciated!
thanks

Tato97T100

I would say, make a saturday morning out of it. Flush the tranny-even though you just did, drop the case, clean the filter, replace the seal, make it all nice and pretty and then drop some more BG in it.

Its better safe than sorry when it comes to your truck. And another excuse to work on it. Which we all like

Al Wilson

97 T100, 88k Shifting problem, some similar issue and some insight, resouces.

al

Howdy,
I've had an light come on, literally, on this problem which I think puts the trouble back into the gear box itself. Let me explain. transdude, owner of IPT, www.importperformance.com transimission suggested checking to see if the ECM was calling for the 1-2 shift at the correct time. I've made up a test light circuit for the #1 and #2 solenoids and as I said above the light came on according to shift schedule, I found the info at www.autoshop101.com where there's an good resource, two different text books loaded with operational and diagnostic help on this trans, in fact toyota A/T in general.
So the ECM is telling my gear box to shift, The solenoids are new so I know they're working but it won't up-shift on it's own. Now I can sometimes treadle the gas and make it shift but the lights show it goes into 3rd, not 2nd.
One other point, in the diagnostics I got form alldata the suggested disconneting the solenoids, external plug/connector on the trans case; drive using the shift lever, i.e. start in low, upshift to 2 and so on.... This they said would show if it was the gear box or the ECM. If it shifts manually then the problem is in the electrics. I did this test and followed the path, ie sensors, contacts, pin voltages, temp. probes, all working fine... So what happen? The data at autoshop, shift schedule shows that with no electrics to the 1&2 solenoids the only speeds available are 1, 3, OD, my problem was and is in second gear.

All that said, I'm back to the gear box, thinking it's a sticky 1-2 shift valve that, according to my deductive reasoning, reacts in this way: cool morning, FL never gets below 40, or prolonged sitting, time enough to allow the valve body/ trans in general to reach ambient temp, 40-80 locally, and the valve hangs, or the spring that pushes it up can't overcome the drag, and no second gear; warm up the gear box/ valve body, by driving, and the ECM makes the call, the solenoid opens, the valve now free enough to move and smooth toyota shift. every time...

Now how to unstick or free up that valve?

PS.
Two other things in the history of this trans, 1. the 1-2 shift valve also is in the Lock up circuit, and if I'm right about this, may be the reason for the P0770 code that use to come up now and again, code books says, Solenoid E malfunction, and 2. no more P0770 codes, but this 1-2 shift issue came about right after I, drained my trans pan and added 3 qts. new dextron III, In essence I, " fixed it till it was broke".

check out these sites, good info,

Al
Still looking for a way to make all the folks who said, " put a rebuilt unit in it and the problem will be fixed ", wrong.

Any Ideas?

elnido

Since I posted this thread a month ago, I haven't had the light go on. I've driven over 1.5k, every type of driving (except extreme 4x4) and the CEL has not come on. I even had the AT/Temp light come on. It went off when I killed the OD. So far so good.
Just an update.
Thanks for your info,I'll have to bite into it when I have more time.

Al Wilson

Eureaka,

I've found it, the valve body had debris in the 1-2 shift valve, and the lock-up valve as well. The shop that did the work, local highly recommended privately owned shop, listened to my long and boring story about 8 months or more of trial and error, and agreed to drop the valve body and have a look.

They found the contamination was making the shift valves stick, cleaned overhauled and reinstalled, viola, shifts like new...

The gear box has 90k on it but it ain't time to rebuild yet... but when that happens, I know where I'm going to get the work done.

elnido

Still dealing with the daily CEL, always the same code, I just kill it with the code reader.
So, what do I tell my mechanic? Clean the valvebody? How intensive/evasive of a process is this?$?, or do I just plan it with the next tranny fluid change/drain?
thanks

naksukow

Cleaning the valve body isn't that invasive and there are lots of write ups. I would be really worried about the AT temp light though. Thats way to hot and your tranny has probably been damaged.

elnido

I always turn off the OD on long haul hills now, haven't seen it in a long time. Truck drives real good. I'll seach.

naksukow

give me your email and I will send it to you

elnido

Thanks for sending that!

naksukow

No problem, if you need anyting else email me. I will have the subscription for 3 more weeks.

Dale Zirkle

Maybe you all can help. I am having similar problems with my 1999 4 x 4 4runner transmission. When its cold it shift immediately in to a high gear, 2nd or third, cant really tell. It dosent happen all of the time and as soon as i drive it 300-600 feet it is fine and doesent happen until it is cold its summer time in NC so the lows are between 75-85 degrees. My 4runner has been well taken care of and it a daily drive never been off roading.
I would apperciate and help or assistance.
Thanks,
Dale Zirkle
CHarlotte NC
704 573-1473

Al Wilson

Hey Dale,

My case was exactly the opposite, when cold my trans would not shift up to the next gear.

But what I found was that there was trash, worn clutch material, in the fluid. I had a trusted transmission shop drop the gear box, clean the valve body and change the fluid, about a 800.00 job, he warned me that the problem may retrurn. Sorry to say it but he was right.

Next step, rebuild. Since then, 1 year or so ago, no problems.

Like I said in the begining your problem may be something different. Lots of controls and feed back loops manage the transmission's shifting pattern and it could be as simple as a mis-adjusted mechanical linkage, shift lever, or failing shift solenoids, bad electrical connection???? all of these and up to and including a rebuild.
Look for some good diagnotics on the web and good luck.

Dale Zirkle

Al,
Thanks for the info, I searched and I cant find anyone that has the same issue is what I am having. I spoke to a mechanic the other day and he said to try a transmission temp sensor first. Would you happen to know where the trans temp sensor is that i need to change?
I checked all of the electrical connection unplugged and pluged them back in several time no luck it still does the same thing when it is cold on occassion. My 4runner has alway been serviced so I cant belive it would be any type of dirt that got in to the system.
Thanks again,
Dale

Dale Zirkle

Would anyone have a diagram of the transmission with all of the assocaited electrical cnnections? I have a 1999 4runner 4x4 with a 3.4 V6 with 133k miles
Thanks,
Dale Z

Al Wilson

Hey Dale,

I don't have that info but there are several inputs you should check.

Engine coolant temp sensor, tells ECU engine temp, my guess is this is in the water jacket of the engine some where,

Transmission Fluid sensor, that tells the ECU how the gear box itself is.

and the third you should check is the speed sensor which tells the ECU if your moving and how fast.

If I were to bet on the problem I'd say check the speed sensor.

But you'll need the diragrams and locations of all these components specific to your year and model.

Good luck

Al

Dale Zirkle

Well you will never believe what fixed it....
Prolong Transmission Lubricant, put it in last weekend and no more problems. You can purchase it at most autoparts stores for around 10 dollars!
Not sure whats in it but it worked for me.
Take Care,
Dale Zirkle
Charlotte NC