tns1

At 200k, my CEL came on and when I had it read, they said "shift solenoid". They didn't tell me the code, and now I see the A340H has a number of solenoids related to the trans: shift solenoid 1&2, lock solenoid, key solenoid.

As for symptoms, I noticed an increased delay when I first put it in drive in the morning before the truck would move forward. It takes about 10sec before it will move. It only does this the first time in the morning, otherwise it shifts and drives great.

The trans fluid is full and clean (but pretty old), the radiator coolant is clean (no pink milkshake).

The most disturbing thing is it makes new noises when it is in drive. From inside the truck, it sounded just like a water pump bearing going bad - random clunks. However, I crawled underneath while someone else ran it thru its paces, and the noise sounds like it is from the torque converter area. It only makes noise while in gear - random clunking like some something loose inside. Some very loud clunks when it is turned off.

My thoughts are to do the tranny flush first:
http://home.centurytel.net/stevenjac...sh/tranny.html

Great links here:
http://www.pirate4x4.com/forum/showthread.php?t=587521

Can I get the actual code by just using a jumper wire?
What connector do I jumper?

Any thoughts on my noises?


Update 6/12/2016 60,000mi on Jasper rebuilt tranny. No issues. For maintenence I drain and fill the trans pan at every other engine oil change (~8000mi). This at least refreshes some of the fluid.
Update 1/29/2023 120,000mi on Jasper rebuilt tranny. No issues.

raydouble

First off, you need someone to diagnose the metal noises you're hearing.
Is your torque converter still bolted tightly to your flexplate? That would be something fairly easy to check.

I wouldn't even worry about the fluid anything until you can figure out if it's even worth putting new ATF and filter into.

You have an A340F transmission, so your link to pirate won't do you much good. The A340H is a different beast that came behind the 3VZ's in the second gen 4runners.

You need an OBDII compliant scanner to pull the codes from your vehicle. Most O'reilly's, Napa etc will do this for free.

tns1

Thanks for the correction on tranny model.

I had the converter cover plate off recently when I did the timing belt. I can pull it off again, but as I recall there isn't much to see. It does sound like small rocks in there though - just random clunks for a while, then that noise is replaced with more of a light whine - whooshing like fluid being pumped. After a while the cycle repeats. This only happens in gear. The truck was stationary during these tests, but does also make these noises while driving.

The noise is definitely originating from the front of the tranny. The key suspects right now are the torque converter, the flex plate, the locking solenoid/mechanism. I'll get the code read again and this time I'll write it down.

I thought at least draining and filling the pan might give me a better check of the fluid quality, and see if any chunks spilled out. I had the dealer do the tranny flush at 60k, but they did not pull the pan. Now its at 200k, so if its not totally dead, I'll pull the pan, flush it, and replace the radiator for good measure.

James Woods

iTrader: (1)

Don't just check the bolts that go to the torque converter either, visually inspect the flexplate as good as you can.

https://www.yotatech.com/forums/f116...-knock-233278/

This may be what is causing your noise.

tunnelmotor99

^^^exactly what I was thinking. The only problem is you will have to remove the trans to fix it, which can be done in the garage with some ramps and a good jack if you are mechanically inclined. I'm not sure of the cost for a new flexplate but they're usually not too bad (once I had to replace the clutch in a Hyundai sonata, which is supposed to have a new flywheel when doing a clutch R&R....$1500 for just the flywheel!)

tns1

So can you just pull the tranny from below, or do you have to pull the engine? Which is easier? I have a full length drive-on ramp and a cherry picker.

tunnelmotor99

You don't have to remove the engine, the trans comes out from underneath. A good floor jack with a transmission adapter will work. Since yours is 4wd you will have the transfer case to deal with also. I'm sure someone on here has done a trans r&r on one of these that has more info than I do as I have yet to pull my trans (189k miles & counting).

James Woods

iTrader: (1)

You don't have to remove the transmission, just pull it back enough to get to the flexplate, I have done it with a come along and left everything connected other than the engine to tranny bolts and the x member, and then just pull it back just enough to get your hand in.

raydouble

Don't forget the rear main engine seal if you're going in for the flexplate.

tns1

It isn't the flex plate. I rotated the engine by hand while inspecting the torque converter bolts and as much plate as was visible. The only thing I can't see is the center bolt ring, but all the pics show them cracking further out than that.

BTW it is now illegal in CA for a parts shop to use the code readers on your car. Has been for a few years apparently. It can only be a licensed mechanic or shop (or you can buy one). Autozone was where I went previously, but no more.

tns1

Listened again from underneath. It sounds like something came loose inside that torque converter and bangs around a bit before lodging somewhere for 10-20secs, then it comes loose again. It will always make the noise when I shift from reverse to drive (or back) and only quiets down if I leave it in gear, but then only for 10-20secs. When I turn it off its like some loose parts bouncing around for a second before they stop - can be some very loud knocks.

Are there any pics or description of the lockup mech? If there is a solenoid for this it must be somehow controlling fluid flow in the converter, but is mounted outside somewhere. It would be nice to find this is all some intermittent electrical problem or gummed up valve body.

I cleared the code and will read it when it re-appears.

tns1

The shifting behavior all seems normal. I can the shift for each gear and for the OD button. How do I tell if the converter is locking or not?

I think I am going to pull the pan on the tranny just to see if there are metal pieces, but before I do I was thinking of running some kind of tranny flush help clean things. I can test the solenoids electrically at that time and possibly clean or blow them out.

tns1

I captured audio of the noise :

http://tns2.00freehost.com/4runner/

You may have to turn up the volume.

I set my mp3 player down under the tranny - Crunch. At 00.12 you can hear my door close and I shift from park to reverse - Klunk, rap, rap.. rap. Then it kind of quiets down so at 1:17 I shift to neutral and then to drive - rap, rap..rap.. At 1:56 I turn it off - Ka-Klunk. Aside from the background engine noise all the klunks and raps are the mystery noise.

tns1

Great photos of A340F pan removal:
http://www.toyota-4runner.org/mainte...ion-fluid.html

Toyota Torque converter manual desc & service:
http://www.autoshop101.com/forms/AT02.pdf

New a340f converter:
http://ariindustries.net/toyota-4run...200234340.html

Various service manual chapters related to A340:
http://khup.com/keyword/a340f.html

Sameera1978

I think your torque converter has bought the farm. Now the question remains on how your front pump is doing. It just might be tranny rebuild/replace time. At the very least I would pull it out and check the torque converter.

J2F42C

Pull the pan first, then test the solenoids using a volt meter using ohms. Check the FSM for the procedure.

http://www.ncttora.com/fsm/

I have heard where people have pulled them and hooked them up to a battery for testing, but have never done it myself. I'd focus on what the internals of the pan look like, and get the CEL cleared. Post pics.

I have seen an old Ford tranny's TC' s impeller shear pieces and still work (not for long), but as speed increased, the noise got louder.

4WD ride?

tns1

Thanks for the FSM post. It eliminates a lot of guesswork.

I wanted to pull the pan, but I'd like to be as sure as I can about the source before digging in. Besides, once the TC is off, it might be pretty hard to tell if something is wrong with it without cutting it open.

I drained a pint of fluid so I could add the Seafoam tranny flush. The drained fluid is old, but clear with no metal. Pulling the pan would show more.

I have been driving around but the CEL has not re-appeared. The noise has not gone away, but is only noticeable near idle. It is hard to tell but I think it goes away at higher rpm, reinforcing the theory that it is inside the torque converter. Enough spin force and a loose part would be trapped against the wall of the converter. Slow down the spin enough, and the part would fall away from the wall to hit other parts.

It is very hard to pinpoint the noise exactly and if I only trusted my ear, I'd say it was inside the engine. The random nature and the fact that it is tied to being in gear, is loudest at idle (and shut down), the delayed drive engagement at first startup, and an unknown shift solenoid trouble code - all this points to the transmission as the source.

Also what is difference between idling in park or neutral and idling in drive or reverse - basically what is the difference in moving parts and forces?

1) A small difference in the engine rpm,
2) A light load is imposed on the flex plate, converter,
3) Trans fluid is pumped thru different valves, etc,
4) The trans front oil pump spins in both park or drive, but maybe there is some increased pressure when in gear.
5) The TC pump and turbine are both spinning at the same speed while in park, and the input shaft and its hub spin too. Once in gear, I believe the front clutch pack engages. The car is stationary, so the input shaft and converter turbine stop spinning. Not sure what the stator is doing (stopped or freewheeling). At any rate, the vanes of pump and turbine are now whipping past each other pretty fast. Any loose object in there would be caught up in the vortex flow and pulled back and forth from pump to turbine, bouncing off the vanes. (see Toyota TC manual).

That's my theory Watson, what do you say?

J2F42C

I'd still say to pull the pan and test the solenoids. Without seeing the insides, all that is happening is purely guesswork.

If the torque converter is grenading, you probably will see some metal in the pan.

tns1

OK, so it finally threw a code again, a few minutes after getting on the freeway, going about 60mph.

The FSM says P770 is a mechanical failure of Shift Solenoid SL, valve body, and/or Torque Converter lock up clutch. Based on the noises I hear, I'd guess the last one, although gummed up solenoid or valve body might contribute to the problem.

I'd like to measure the pump pressure as described in the FSM. Any idea what thread is on the plug used for this?

J2F42C

No clue on how to measure the pressure that way, it may take an Toyota SST to perform such. If you want a pressure reading, the best bet would be to take it to a shop.

The only way I have ever seen ATF pressure measure is with a gauge screwed into a port for a remote spin on filter for the ATF on diesel trucks.