Transmission Aisn Warner 340 series transmissions ( WRITE UP ) Your 4 speed automatic

Sounds more like a torque converter issue to me .
There are Torrington bearings inside the torque converter that are common for making similar sounds to what I heard in your videos .
I beleive a stall test would help you narrow things down
Transmission pumps also make a similar sound
These transmissions can go a million miles making this noise .
When was the last time you had the transmission pan off ?

 

I have personally never removed the pan, but over the life of the truck, I have had Toyota perform a full trans fluid flush two times. Once at ~90K and again at 175K. I assume they did it correctly by removing the pan but I cannot be certain of that.

It is reassuring to hear that the noise may not imply imminent problems. It is disconcerting nonetheless. The last thing I need is a trans failure 1500 miles from home in the middle of death valley.

I will do a stall test tomorrow. I just saw a video that describes how to perform one. Am I reading this spec sheet correctly, that the expected stall RPM is 2200 +/- 150?

 

@gearcruncher I ran the stall test today. Everything seems to be in spec as far as I can tell. Here's a video of the event. The tach and my scangauge shows the RPMs held steady at ~2165. Does this info add anything new?



And to follow up on your question about when the last time the pan was dropped, as near as I can tell, it has been about 50K miles. FWIW, I have started doing drain and fills. Two so far. Most recent was at 209K, which was 16K miles ago.

I am planning to install a supercharger soon and have purchased the transgo reprogramming kit and a new filter. Is this a bad move considering what may be happening with this transmission?

 

The stall test basicly tests the integrity of the converter and clutching used for forward movement . I was hoping you would have heard your noise increase and decrease as you stall tested .
The stall test places a lot of load on the converter but I couldnt hear the whine in your video during the stall test
I hate diagnosing noises over a keyboard .

There are at least 4 possibilities off the top of my head

1- the converter bearings
2 - the fins on the converter stator and impeller
3 - transmission pump is starving for fluid , either the fluid is low , the filter in the pan is plugged or the pump is wore out .
4 - the pressure regulator is resonating in your valve body due to valve body wear . .



If you are going with a supercharger , it may be worthwhile to find a good working spare trans

 

@gearcruncher I was wondering about that. Since the whine essentially do not show itself during the stall tests, I did 4 or 5 of them all total, and was unchanged afterwards, the likelihood of the issue being the torque converter seemed to lessen.

Fluid level is not low. If anything, it is just a bit high. While I can't measure fluid flow, it would seem that there is good flow based on the scangauge's trans temp readings and how responsive those fluid temp changes are.

Earlier you suggested that these transmissions can go a long time with a whine noise like this. If the whine is a pump starvation issue pulling the pan and replacing the filter seems like it would be worthwhile trying before giving up. In your opinion, if I add the transgo kit wile I'm in there, does that have he potential to make things worse, or will the kit not effect the performance of the pump? I guess I don't fully understand all that kit will do. I know it will reduce slippage and improve the shifts and therefore help to reduce heat generation. Is there more to it than that?

I totally get what you are saying about diagnosing sounds. Thank you very much for the feedback you've given, it is very much appreciated.

 

You said you were a 4wd. Have you checked your transfer case lately?

The transgo kit increases the overall pressure of the system as well as opens specific holes to allow quicker shifting. I would highly suggest the truck setting instead of the hot rod setting when you do it. Hot rod setting is a bit too much.

 

Yeah, I've read some of your post about that. I was thinking the truck setting is the way to go too.

Do you know how that kit increases overall pressure? Does it make the pump work harder or does it remove restrictions?

As for the tcase, I had not considered that. I suppose it could be a bearing on the main, pass through shaft. The fluid level in the tcase is good as It hasn't been very long since I last changed it. I will verify that it's not low.

 

Yeahhhhh hot rod was a bit too hard lol I was worried about shocking the clutches.

The transgo kit uses stronger springs, shims as well as you remove some of the check valve balls so its a little of both.

 

There are also valve body components available from Sonnax designed specifically for known issues in the A340 series transmissions .
Toyota transmissions are known for valve body wear .
Have a peek at their website
https://www.sonnax.com/parts/2764-zip-kit

 

Will do. Thanks.

 

Glad to see that this thread is still active. I’m having a small but annoying transmission problem with my 2000 4Runner V6 4WD with I believe the A340F transmission with the line pressure cable. Correct me if I’m wrong on the transmission name but I’m positive it has the line pressure cable because I have been adjusting it for the past year trying to get this problem to go away. Anyways, the transmission has never given me any codes or not shifted into gear, however it shifts really hard most of the time at medium throttle. It’s pretty smooth and acts normal at less than 20% throttle or greater than 80% throttle. But in the middle it shifts pretty hard. They all seem pretty positive but it’s not a quick jolt it’s more of a little shudder. It’s never slipped or not shifted and has plenty of power for what it is.

Here is what I’ve done in order to try and fix this issue:
- Drain and filled multiple times with Valvoline Maxlife ATF
- Replace transmission filter and added external cooler with inline magnifine filter
- Replaced both throttle and line pressure cable
- Greased rear end of driveshaft because it was clunking at stop lights when releasing brake petal(fixed that problem but not shift problem)

This is probably not related at all, but since doing those things, I also replaced my muffler with a louder one and can hear the shifts now, they sound very clean, crisp, and smooth but still has a bit of jolt when shifting. Only way I can seem to get it to go away is WAY loosen the line pressure cable but then it doesn’t like to downshift.

Also, when pressing the gas petal while car is at speed, (enough for the car to have to downshift) there is an initial clunk then it downshifts, which is EXTREMELY annoying cause it feels like something is breaking.

Trans temps usually stay between 150-175F.

@gearcruncher ive read probably every forum on the internet about people complaining about transmission problems and none of them seem to be similar to my problem which is why I still have hope for my transmission. What do you think?

Any input helps, thank you!

 

The adjustment procedure for the cable is on the first page at the bottom of the first post in pdf format .
it sounds like your cable is way too tight.

Those cables do stretch over the years and need periodic adjustment .
If you dont make adjustments to the cable from time to time , the transmission begins shifting very lazy to the point where its almost slipping.
A good time to look at the cable adjustment is when you do your routine transmission servicing

That cable tells the transmission where your foot is on the gas pedal
When the cable is too tight , the transmission thinks you have your foot mashed to the floor so the transmission ramps up the pressure to compensate ....upshifts will be late and agressive

When the cable is too loose , the transmission thinks you are hardly into the gas pedal , so upshifting will be very early and super smooth to the point where you may not feel the transmission upshift and downshift ...Not good .

Most guys prefer a crsiper shifting transmission . I certainly do
The less time it takes for the transmission to shift reduces friction and heat build up inside the transmission .
Try telling that to a soccer mom or grand parents out for a Sunday drive .
Thats why Toyota engineers design a little slip in the automatic trans . Gotta make everyone happy .

Then there are the guys seeking the 1200 horsepower upshifts that throw you back in the seat when the trans shifts . Thats not good either . The planetary gears inside the transmission can only handle so much load .


What did the bottom of the pan look like when you replaced the filter ? was the pan full of junk ?
Whats the mileage on the transmission ?
If i had to guess , you have worn valve body components in the line pressure loop . This is usually caused by lack of fluid changes .
Your issue is a common complaint with the A340 series transmission . I see it often
I suggest following the cable adjustment procedure , then we can dig a little deeper if the adjustment doesnt solve it

 

Thanks for the super fast response! I’ve read all about the adjustments for the cable, the little nob should be 1mm to 0mm out from the sheath. I did that and it made the shifts insanely hard. I will attach a picture of how loose it had to be for the shifts to be smooth. I will also attach a picture of the bottom of the pan, it had the original Toyota gasket maker on it so I’m assuming it has never been removed before my ownership. I replaced the line pressure cable cause I heard from someone else on the forum that it could be worn.(old cable in picture) The new one, OEM, does not have the little metal nob on it. Is there another way to get it close to adjustment without using the nob? The car has 205k miles. All original parts.

 

Also, the fluid that I drained out originally around 195k miles was dark. It wasn’t burned and when put on a white paper towel you could still see a dark dark red color.

 

There is another way to adjust the cable according to pressure but requires a zero - to 300 psi pressure gauge . There are pressure taps on the side of the transmission . I dont think the cable is the issue . The valving inside the valve body that your cable controls is the issue . They call this erratic line pressure control
Those valves stroke 10,0000 times a day
when the fluid is dirty , the fluid works like sand paper on your all aluminum valve body causing the spool valves to seriously wear out
I think its time for you to visit the Sonnax website , punch in your information and see what they offer to restore the hydraulic integrity of your transmission .
https://www.sonnax.com/units/283-a340

 

I’ll check that website out. Is that fix something that’s easy to do? I don’t know much about transmissions and automatics especially scare me. Haha. Is there anyway to determine for sure? And would that problem cause that clunk prior to downshifting when accelerating?

 

Yes , there are accumulators inside the valve body ( cushions ) that also wear out but I believe strongly that your main issue is the valving for erratic line pressure .
Sonnax has the kits to fix this .
There are write ups on how to do it .
Take lots of pictures and go slowly .
It will take you a day to install the kit .
Trans shops charge 800 bucks

 

Wow! That’s great news. I will order them and give it a shot. I see there are 2 ones to choose from… Boost Valve Kit 97855-23K and Boost Valve Kit 97855-30K. How do I know which one I need? If I don’t do this immediately, will I cause more severe damage to my transmission?

 

See if they have a zip kit for your specific trans .
That would be the best approach .
You will need to order valve body gaskets from the dealer .
Have your vin number handy when ordering the gaskets

You will not do more damage if you keep the pressure higher .
Live with the clunk and late hard upshifts until you install the kit.

Go to the 1st post in this thread and download the overhaul manual for your transmission . Read through the valve body circuits to familiarize yourself

 

This thread looks like solid gold. Just acquired a 1995 1UZ with A340e trans. No tcm - anyone know if the trans controller was incorporated in the ECM? thanks