avg_dude

87 4runner , 160k, 22re, A340H tranny, with rebuilt motor. Frequent reader, first time post. I’ve combed through the forum numerous times, but I’m still stumped. My rig was a cheap purchase, but it’s taken a lot of money and time since. My wife is about to disown me with the rig.
The problem I’m having is the auto tranny’s shifting in and out of 3rd. It shifts through 1st and 2nd fine. As the rpm increases (2500) approaching 3rd, it’ll drop to 1800, than jump back to 2300, than drop again to about 1600 and the vehicle will again accelerate. It acts as if it can't make up it's mind to advance or not. It’ll continue to accelerate through 3rd fine and it’ll do it again leaving 3rd going into OD or 4th. It does this in “D” , O/D on or off. In “PWR” mode it’s not as bad as in “NORM” mode. If you manually shift from L-2-D, than engage OD, it’ll do fine. Also, if I do a real gradual Granny acceleration, it’ll shift through fine.
No ECU or ECT diag codes. The ECT code was a pain in the ass endeavor. Even though my Diag box has an “ECT” slot labeled, I could not get any codes not even an “OK” light. After I dug out the grease covering the “ECT” socket, I realized there was no wire underneath. I finally found the “DG” socket on the other side of the engine compartment.
I’ve changed the ATF and filter, front and rear diff, and transfer case fluids. Installed new fuel filter, pcv, cap, rotor, cables, plugs, O2 sensor, OEM thermostat, and ECU temp sensor. Checked and rechecked ATF level. I’ve checked the throttle cable, checked and rechecked the TPS. I checked the resistance level of the 4 solenoids via the ECT connector. I applied voltage to them and heard each one engage and disengaged. I've jacked up the rear and checked the #2 speed sensor.
I’m running out of options. I’m suspecting the ‘lock-up’ solenoid, but it passed the resistance and voltage test. Any ideas would greatly be appreciated. I’m trying to avoid going to the stealership.

average dude

bikeguy18974

I've got an 86 4runner with the a340h.

I have a similar problem to yours but I don't have a tach so I can't compare rpm's for you. I do notice the rise and fall of the rpms though.

I'm not sure if yours is worse than mine but mine's done it since the day i bought it. I just assumed that is how a toy auto trans with 170k shifts. I've put about 10k on mine since purchase. I've changed fluid and filter as you have, plus added an external tranny cooler and inline filter. Its always the same. I'm going to just continue assuming its supposed to be like that, knowing that I may need a new trans in the future.

avg_dude

I thought the same... maybe it's just how it suppose to work. I don't know anyone else with the same vehicle to compare. Thanks for the insight. Anyone else expierence the same?

mtnfreak

Sounds like the torque converter going in & out of lock-up mode. Mine does something similar, but much less extreme. Have you had the tranny power flushed? That's the only way you'll be able to change out the fluid in the converter - I supsect most of it is well past it's service life. You can probably get a local shop to do it, along with a filter change, for less than $100. If there's not a write-up on the tech pages about how to do it yourself, then I know there's a thread about it somewhere on this magnificent forum.

avg_dude

Thanks for the info. Does anyone know if the lock-up solenoid is disengaged when manually shifting? I don't have a factory manual. The Haynes is really limited dealing with an auto tranny.

mtnfreak

Checked my FSM & it doesn't say, but shifter position is not listed among the instances that would cause the Torque Converter to be locked into one mode or the other.

avg_dude

And the band plays on... Thinking back, I remember my TPS didn't increment in 1volt steps. At a point it would occasionally go from 4 to 4.5 than 5 volts. I thought the undefined 4.5volts may be messing up the ECT brain. I replaced the TPS with a better working TPS from a junk-yard, but the problem still exist.
Something I've recenlty notice, as the tranny does it's odd shifting I hear a 'thump' in the tranny. Not a metal to metal but a low, muffled thump. Again if i do a granny takeoff or manual shift it doesn't make the noise.

Toddski

My '88 4runner does the same thing
Guess i kinda just lived with it.

89_4runner

avg_dude, got your pm. I'm still reading the FSM, but I would recommend a Manual Shift Test. Unplug the ECT located in front of your shift lever. Then, you can operate the transmission without electical control (ie. solenoids).

L range is 1st, 2 range is 3rd, and D is O/D

When my #1 solenoid went out, I drove like this for weeks until I could replace it.

avg_dude

Excellent, I'll try that. I didn't realized you have to disconnect the brain first... duh. I manually shifted and I thought that would override the brain. Thanks

avg_dude

Okay... I disconnected the ECT and the vehicle drove fine with manual shifting. I did notice at 55mph, I was about 500 rpm higher that normal. Is that because the lock-up solenoid has been bypassed?

89_4runner

Could be. I'm not an expert in transmissions. I just read the Toy manual. The good news is that if the trans worked fine with the ECT ECU unplugged the problem is electrical and not mechanical (expensive rebuild).

The manual mentions that you can check for lockup by driving at a steady speed of 47 mph with the trans in O/D. "Lightly depress the accelerator pedal and check that the engine rpm does not change abruptly." Of course, do this with the ECT ECU plugged back in. I'm not sure why 47 mph is important.

Just to confirm... You said you checked the ECT ECU for codes thru the DG terminal. Did you get the O/D light flashing on/off every 1/4 sec? I ask because I had to replace my O/D light to read the codes last year.

I'd try the lockup test and then drive with the ECT ECU unplugged for a couple of days to be more confident. It shouldn't be real difficult to replace the lock-up solenoid.

avg_dude

yup, I have a 'ok' flashing light from the codes check. I havn't purposely check the '47mph' test yet. I'm confident from memory that the rpm does change abruptly. I will at next chance do that check though.
By the way, did putting the headers give you any extra power? did it change your miles/gallon?

89_4runner

It's possible that the lock-up solenoid is plugged and not throwing a code. I would say if you try the '47 mph' test and you get much revving to drop the pan and test/change the solenoid.

From the FSM:
Check the lock-up solenoid valve.
* applying 71 psi of air, check that the solenoid opens.
* apply battery voltage to the solenoid and check that the solenoid valve does not leak air.

I can recommend buying the solenoid from Transtec or Transtar. Goto my link in this earlier thread.
https://www.yotatech.com/forums/f2/code-62-help-1-solenoid-pull-where-41903/
They sell generic solenoids much cheaper than Toyota.


Regarding the headers... I added them 10 years ago when I was running 33's and thought they gave some slight improvement then. Now I'm running 31's and my truck accelerates around town ok, but has no power at ~65 mph (just like when I ran 33's & 35's). Of course the engine and transmission have a bit of age and miles on them. I'm getting 17 mpg with highway driving at 65-70. When the truck was new with 225-75's it easily got 20-21 mpg on the highway. What sort of mileage do you get with you're rebuilt 22re?

avg_dude

I did the 47 mph test, and yup she jumps in rpm, worst at 37 mph (going into 3rd). I think your right about the solenoid being plugged. It's not holding at lock-up, which causes the tranny to go into 3rd and O/D early and the acceleration is extremely weak.
The wife has put me on "holiday season budget mode" so I'm gonna have to wait until the New Year before I can get a new solenoid. Thanks for the heads-up about Transtec. I've searched the net but have not found an after-market solenoid. The stealership wants $180.00. New gasket, ATF, and solenoid would be an easy over $200.00 job. So it's gonna have to wait till after Xmas.
I wish I could check the solenoid with the air test without having to get a new gasket and fluids. At least I would know for sure and settle my mind. I did read somewhere that Toyota was known for getting clogged solenoids. So I'm like... I should do all the solenoids, and have the valve body re-done while I'm at it. But we're talking about some serious money. Consideration of selling a kidney comes to mind... lol
Hey guys, I really appreciate the help and info. I've always wanted an old school
4Runner. A wife and 3 kids, I had to get one I could slowly fix up. Right now I'm just trying to get it mechanically sound before even starting on any cosmetic and performance stuff. I just wanted to say thanks for the input and info.
As for the gas mileage, initially, I was getting 17-19 mpg. I keep track of my mpg since my fuel gauge likes to stick at 1/4 tank when the tank approaches 1/2 tank. I've read you have to drop the tank to change out the sending unit so it's another project on the "to-do list". I live on the outskirts of the city and most of my driving is on rural highway but I do venture into the city. After the rebuild I started getting 19-21mpg. I changed both diff. oil and added some Lucas oil as per manufacture's recommendation. I don't know if it's coincidence or the engine broke-in, but occasionally I get up to 22 and 23 mpg (again mostly rural highway with some traffic lights). I also run on the higher octane (92 or 93) sold. I'm not a lead foot, and I typically cruise at ~60mph. This is a pure stock rig, no mods yet. Even the stereo is original. I hope to do better once I drop in a K & N.

89_4runner

I understand if you need to wait, but you can replace the lock-up solenoid for more like $100.

If you live in/near Moyock, NC (from your sig) there is a Transtec distributor, ATC, in Norfolk, VA. There are also several other Transtec distributors in NC. Take a look...
http://www.transtec.com/distributors.htm
http://www.atcdg.com/Locations/loc-Southeast.asp

They will sell solenoids and gaskets for the A340H transmission. I bought my parts from their distributor, Transtar, in TX. I bought Rostra solenoids (shift 1 & 2) for less than $100 for the pair. The pan gasket was ~$5. I talked to ATC in Dallas last year and I think they will sell the solenoids individually for ~$50 each, but I think the lock-up one is slightly different.

Here is some interesting reading on the A340...
http://www.transtec.com/specific_trans/a340.htm