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

You are waisting your time taking it to the Toyota dealer . They will just try to upsell you a transmission .
I like your first idea better . Take it to the local trans shop and let them have a go at it

 

My local transmission shop came through! It was corrosion at the connection between the wiring harness outside the transmission and that inside. Most of the pins were gone (rusted away) and there was signs of burning from the resulting damage. They were able to order a new internal harness (they called it a pigtail) from Toyota for $285 Canadian. They could not order the exterior harness that goes from the ECU to the connection on the transmission - Toyota would not sell that part of the wiring harness separate from the main wiring harness which was $3600 Canadian. Fortunately the shop was able to locate a used one for $185 Canadian. My total came to just over $1000 including labor and it's back to working normal. So it was an electrical problem. My lesson here is to use dielectric grease on connections every couple years. Our climate here sucks in winter for snow, and the salt they use on the roads.
Thanks for your help.

 

Well, things were going great with the new wiring harness' but I just got a P2759 code.

According to this:
http://www.customtacos.com/tech.old...06toyrm/06toypdf/06rmsrc/rm2006ta/0260024.pdf
its a Torque Converter Clutch Pressure Control Solenoid Control Circuit Electrical (Shift Solenoid Valve SLU) problem.
This diagnosis calls for resistance testing of the connections at the wire connector from the transmission. Sounds like I'm not out of the woods yet.

 

I've been getting a p2757 code which is very similar. I have yet to address it but will be soon

 

@gearcruncher quick question... I've got an 03 DC 4WD with 342K on it. I have the transmission flushed once annually and never had any issues. Recently I've been getting the following symptoms and I'm wondering if it's just that time for a trans rebuild/new trans or if there is something else I may need to look into:

- When I slow to 5-10mph and take my foot off the gas pedal (say if I was in the turn lane turning onto a side road) and then reapply pressure to the gas pedal to accelerate, the RPMs will rev slightly and the gear will catch. The sensation is similar to if the truck was in neutral and then I shifted into Drive.
- This happens in 2nd, Drive, Reverse, etc. Same symptom throughout. Sometimes it rougher than other times. If I ease on the gas then it will rev and just ease into movement.
- I also get some pushback under heavy acceleration. It's sort of an accelerate/lag, accelerate/lag sensation until it pulls through. Not sure if this has anything to do with the symptoms mentioned above.

Any help on what route to take to diagnose my issue would be greatly appreciated. TIA.

 

Kind of a stupid question but have you checked you fluid levels recently?

 

Negative ghost rider. I had the trans serviced (flushed) by a trusted mechanic who's kept the ole gal running like a champ. I have faith it was flushed/filled correctly...

I'm fairly handy, but have very basic knowledge when it comes to engine, trans, electrical maintenance on these beasts. Would that be where I should start?

 

I mean If you've checked your oil before it's the same thing but different dip stick. It's a free way to check.

 

Gotcha. I'm definitely capable of checking the fluid. If it's a standard level, any thoughts on where I should go from there? I only ask because the guy who services the vehicle gives me a heads up if anything pops up that needs to be fixed (example: I had a small crack in my radiator last time I took it in). He didn't notice anything out of the ordinary when he flushed the trans about 1.5 months ago.

 

As mentioned above , start your truck and let it warm up . With the engine running , check your trans fluid level in park with the motor running
Once we have confirmed your fluid level is good , we can start troubleshooting but as far as I am concerned and judging by your explanation of the problem , you have low transmission fluid . Its very uncommon to expierience symptoms in more than 1 gear and you are having issues with a few of them .
Fluid level check first and then we can move on from that point forward
Keep in mind that your engine has to be running to check your trans fluid . When the engine is running , your transmission pump is turning which keeps all the hydraulic circuits filled with oil . If you check the dipstick with your engine off , the fluid level will show way way above the full mark . Lotta guys make this mistake

 

Hey gearcruncher, are you still around?? You'll probably have my answer. I have a 2013 Taco. reg. cab, 2.7, 4X4, auto. a A340F. I'm considering going from the oem 4.11 gears to 4.88. This gear change would increase appx 375 rpm. @ 60 mph. From watching my tach. & speedo. If I push the gas pedal enough to unlock the torque converter @ 60 mph. my tach. goes up appx 350 to 400 rpm., but it won't stay there long, it either locks back or shifts down to 3. I can touch the brake pedal slightly & the converter will unlock, but then the elect. accelerator won't work. What I'm wanting to do is be able to disable the lock-up, & drive around my area for a couple of days with the converter not locked, mimicking what the 4.11 to 4.88 would be, to see if the appx. 375 rpm change is what I'm looking for. Kind'f like trying out the gear change before doing it. The gear change is pretty expensive & I'd be very disappointed if I paid for the change, then found it didn't suit me. It seems if I could find a way to either drive in 3 & make the converter lock, or drive in OD (4) with the converter unlocked would accomplish what I'm wanting try. Any help appreciated.

 

I think the easiest way to do this is by disconnecting the electrical plug where it goes into the transmission casing . Thats the electrical plug that goes directly to your converter lock up solenoid inside the transmission .
Once the electrical plug is removed , you are going to get codes cuz the computer sends a command to the lock up solenoid and doesnt get an answer back .
You wont do any damage if you drive around for a day or two for testing , but you should use the converter lock up feature . running without lock up creates a bunch of additional heat

 

Hey, that's what I was hoping for. I don't know how many plugs are on this trans, but can I assume the one I'll be looking for will be the one closest to the front, nearest the converter? Am I missing anything, will what I'm trying to do have about the same feel as the 375 rpm. gear change while driving down the hwy. @ 60 or 65 mph.? I know the gear change will affect driving in all gears while the converter disable will only affect hi gear, but won't this tell me what I'm trying to find out? Thanks a lot.

 

I doubt leaving the converter unlocked will give you the results you are seeking .
When the transmission upshifts into 3rd gear , its direct drive directly off the motor that makes a 1:1 ratio
All the lock up solenoid does is lock the impeller and turbine together to eliminate the slipping inside the converter . The rpm will drop 300 to 400 rpm when the converter is locked up .
because you are changing the final drive gearing , all shifts will take place sooner .
You will have all kinds of torque and low end power , but your top end will suffer
I beleive the converter locks up in 3rd as well as 4th in your 2013 Tacoma .

with 4:11 gears , lets say the engine revs at 2300 rpm at 65 mph in 4th gear with the converter locked
With 4:88 gears , your engine rpm,s will be closer to 2700 at 65 mph in 4th gear with the converter locked
More gas and engine wear with the 4:88 ratio

 

Naw, someone else also thought the converter locked in 3 as well as 4. I've played with it again & again. If I drive along on level road @ 60 mpm. in 3 the tach is at appx. 2800, (more rpm than I want to run on a daily basis) when I move the shifter to 4 the trans. will shift to 4th, & the rpm. will drop to appx. 2400, then a few seconds later the converter locks & the tach drops again to appx. 2000. Shifting back to 3 it jumps back up to 2800 but does it fast enough you can't tell it both unlocked the converter & shifted to 3. Now while driving along in 4 at 60 mph. (2000 rpm.) & mash the gas far enough to unlock the converter, but not shift to 3 & the tach jumps up to appx. 2400, That seems to be about where I feel comfortable daily driving, but it won't stay there for very long till it either re-locks the converter or shifts down to 3. If I can drive it a while keeping the converter unlocked, 60 mph. @ appx. 2400 rpm. up & down hills as well as on level ground, I'll be able to tell how & if it climbs hills better without shifting & if the rpm's seem too high for daily driving. I realize with the converter unlocked, it will not change anything while in 1, 2, & 3, & if I decide to do the gear change it will have more torque or pulling power in all the gears. Now, to find the correct plug to disconnect. Thanks again, I think this is exactly what I've been looking for.

 

Hey Gearcruncher,

Lots of GREAT trans info here, thanks!

I've got a Supercharged 98 T100 I want to swap an A340 in it, In addition to a Transgo shift kit, what else do you recommend to build a bulletproof trans?

 

Its a good transmission and even better once you install the shift kit . What are your plans for keeping the transmission cooled ?
https://www.tacomaworld.com/threads/transmission-coolers.526283/

 

Another great write-up! I was planning on aftermarket cooler, hadn't got to specifics yet.

Just want to get a list of everything I need before I start turning wrenches.

So do you think I should look into valve bodies or any other upgrades?

Thanks again!

 

If you are mechanically inclined , installing a shift kit is one of the smartest things you can do to improve the durability of the transmission . A must when combined with a supercharger . The trans-go shift kit saves you from spending $600 bucks at a transmission shop such as IPT or level 10 having your valve body built up and your truck down for a couple weeks .
When these trucks are sold at the dealership , they have to please everyone meaning they have some slip built in . Sunday drivers and soccer moms are happy ,but with this being said , the A340 series transmission needs some attention when you add more power , armor or larger tires
Have you read Rldanie write up ? He did a fantastic job on his valve body https://www.tacomaworld.com/threads...t-install-with-pictures.632542/#post-21714646

 

That's a great write-up, will be using that for sure. Thanks for the link!

So is installing the shift kit the same as having the valve body built up or is that something different?