3rd Gen Torque Converter and Transmission Replacement

I know there are threads on torque converter shudder but I thought I would share my experience. I started experiencing a bad torque converter shudder around 40k miles on my 2018 sport. Bad as in rattle your teeth and borderline undrivable. It was the worst between 3-4th gear regardless of rpm. Shudder would go away after shifting to 5th. No hard shifting was noticed with smooth shifts through all gears.

My issue was more noticeable with transmission temperature. Didn’t really notice a shudder after cold startup but it would start to show up after 10 or so minutes of driving.

Took it to the dealer and they initially said the TC was failing and needed to be replaced. After the new TC showed up (not installed) a different tech did some more “diagnosing” and said that alone will not fix the issue. They said the trans needed to be replaced as well. Didn’t get much of an explanation (yet) but will report out if I find out anything additional. All is covered under warranty but a bit concerning about the reliability of these 3rd gen TC’s if that truly is the failure point.

 

@gearcruncher

 

If the converter shudder was at the point where your teeth would chatter , then yes you definetly need a converter . The torque converter is only half the repair . The valve body inside the transmission controls the pressure holding the converter clutch to the converter clutch dampner . Dealerships no longer work on valve bodies as I understand it

Its not uncommon in mass produced vehcles to get a few bad converters . Maybe the torque converter clutch facing wasnt baked correctly at the factory .

I have had a lot of new converters fail on me . Over the years , at least 75 bad converters at the trans shop. Thats a crappy pill to swallow both for the customer and me . I have to remove , rebuild and re-install the transmission twice . Sure the owner of the truck gets warranty but how do I recover the time and parts/ new fluid and pay the guys to do the work ? Sometimes its very difficult to prove the converter failed considering the valve body and computer control come into play .

Torque converter clutches are programmed not to apply until the transmission warms to operating temps


Maybe your transmission was low on transmission fluid for the 40K before this started to occur . This is very common and highly likely what caused the problem .
The AC60 series transmission needs to be filled properly to the full and dribbling point . I cant stress this point enough that these transmissions do not function well even with a few ounces low
https://www.tacomaworld.com/threads...be-low-on-fluid-directly-from-factory.405642/

If you have a transmission pre-heater , there is a possibility the manual valve failed which holds your transmission fluid in recirculation rather than circulating trans fluid through your cooler . I do not like pre heaters at all . In fact there are kits in the aftermarket to bypass this OEM feature

When the torque converter starts failing , tiny particles of metal and friction clutch material travel through your complete transmission fluid acting like sand paper throughout the entire transmission . This does serious damage to your " all aluminum valve body " and is the top reason we need to keep the trans fluid as clean as possible
This is most likely why the second technician recomended a complete transmission replacement . Its possible he removed the pan and found all kinds of metal and clutch material travelling through your valve body circuits .
There are fixes for a chattering converter without removing the transmission but you have to catch the issue as soon as you notice it .

1 - keeping the transmission fluid as clean as possible . Frequent servicing with highly friction modified fluid conditioners .Lubeguard Platinum
2 - Aftermarket tune to prevent the converter from partial lock up in 2nd , 3rd , and 4th
3 - Aftermarket valve body kit that also prevents partial lock up in 2nd ,3rd and 4th . The aftermarket valve body kit thats presently in production provides greater holding pressures for the converter clutch when you are in 5th and 6th gear but they are not available to transmission shops yet .
All you can do now is the Nomad kit
https://automatictransmission.com.au/shop/nomad-heavy-duty-valve-body-to-suit-toyota-hilux-6-speed/

 

Had mine changed at 85000 miles 2016 off road. so far 12000 miles and no issues.

 

Question. What is acceptable atf fluid temp in TC?
Tunes can turn partial locking by shutting off SLU, but this is causing TC temps go up. Think are getting to warm in slow driving/ traffic
If SLU is off, is there a mechanism for a heat exchange?
Thanks.

 

Thats a great question
Hmm acceptable torque converter temps ? I think 170 is a good target to maintain if you are watching your temps . Aftermarket coolers should be considered for heavy stop and go traffic at slow speeds

Toyota designs the converter in the AC60 series transmission to partially apply the converter to save fuel and be competetive with other vehicles ..GM Ford and chrysler
Think of a guy with a manual transmission slipping his clutch in 2nd , 3rd and 4th every day a thousand times in a short drive cycle .
This is what a factory torque converter inside the AC60 series transmission is doing on a daily basis to save fuel. This gas saving feature is incredibly demanding on the lock up clutch friction surfaces .
If you go back 15 years in transmission design , there was no partial torque converter lock up in 2nd 3rd
The early 4 speed automatic transmissions in the 4 cylinder Tacomas with the A340 series transmission did not partial apply the converter in 2nd or 3rd and there were no issues with heat build up . Once the transmission shifted into 4th gear , the computer then commanded the torque converter to shift into lock up and any heat then dropped immediately .

To answer your question : If you install a valve body kit or tune to prevent the converter from partial apply in 2nd 3rd , I doubt any additional heat would be noticed .
As soon as the trans shifts into 4th at low speed , the converter is going to lock and any heat build up will drop quickly .
When the SLU is off , transmission fluid leaving the converter at its hottest point still travels to the trans cooler to be cooled and then back to the pan .

 

@gearcruncher I appreciate your detailed response. Thank you!

 

the TC temps can easily reach 210 especially in the summer/mountains. and that's without towing anything and zero weight in the bed.

 

Is using lubeguard platinum on transmissions without issues common practice? What is it adding that the WS fluid doesn't have and if it helps why aren't they Using these ingredients in the trans fluid ?

 

I've changed a lot of TC's on Toyotas. Like hundreds.

I've yet to have a shudder on a Tacoma. But if its mild a TC is all you need.

That said, Toyota tech's arent transmission experts. If they are concerned about their diag, they will cover their bases with a whole unit.

I've only had to change a handle full of toyota transmission's due to TC shudder, usually its violent and shakes the dash. Very rare.

Most TC replacements is TC, pan flush, software reset.

Edit: They all happen hot. All of them.

 

Lubeguard is like a catalyst and supercharges your regular old WS fluid .
Its the synthetic LXE additive in Lubeguard that makes it works so good with Transmissions and locking torque converters .

Why OEM doesnt use these ingredients ?
I do not know .I am assuming they have a contract with a lubrication supplier already and maybe they beleive the friction modifiers in the OEM fluids are good enoughfor the general public .
I certainly do add some in every single transmission I overhaul as well as service .
I have a contract with valvoline and can tell you for sure that I get some crappy shifting and some crappy shuddering after I overhaul some transmissions . Lubeguard will clean those problems up if minimal

Is it common practice to add lubeguard Platiinum to a good working toyota AC60 series transmission ? you got my blessing to throw a bottle in there
What you consider working good and what I consider working good are 2 different animals .
I am not a Lubeguard salesman lol but I do endorse their products 100 %

Lubeguard was never available to the general public 15 years ago . You could only get the stuff in transmission shops and dealerships and you paid big bucks for the stuff .
Now that its available at Amazon and affordable , I recomend to everyone to throw a bottle at the transmission when you service your trans .

Dont get me wrong . There are snake oils out there that are a 1 time use that work with heat . If you continue to operate your transmission after adding these snake oils , your transmission fluid turns to acid . You have to change your trans fluid after using them . Lubeguard is designed to remain inside the transmission working with your fresh WS fluid until its time to service the trans again . Thats when I throw another bottle at the trans

I try to explain things at Tacoma World so everyone understands
For a better understanding , check out Lubeguards website . The results are proven by many members at Tacoma World and every possible transmission shop that I know of .
https://www.lubegard.com/automotive/#submenu1

 

@gearcruncher so, on a newer low mile 3rd gen tacoma how much lubeguard platinum would you suggest running? 20oz? thank you in advance. Ski

 

If you beleive the transmission is functioning fine , 10 ounces should do the trick

$15 Lubegard 63010 Platinum Automatic Transmission Fluid Protectant, 10 oz.

https://www.amazon.com/Lubegard-63010-Platinum-Universal-Protectant/dp/B002MB57UI?crid=1O2U9LHN7GIXB&keywords=lubegard+platinum+for+transmission&qid=1644291072&sprefix=lubeguard+pla%2Caps%2C153&sr=8-1&th=1

During a transmission pan drop for screen replacement and pan inspection , magnet cleaning , I will do 15 ounces
During a transmission pan drop for screen replacement and pan inspection , magnet cleaning followed by a flush permitting the pan was clean , I will do at least 20 ounces

 

When do you recommend a pan drop on these ? I just turned 30k and am going through all fluids. I bought twelve quarts and was going to do three 3 quart fill/drains.

 

The company that builds your Asin Seiki AC60 series 6 speed automatic say to change the fluid every 35K .
However if you follow Toyotas fluid change interval in your owners manual , its much longer under ideal conditions . 2nd gen is 60K under ideal conditions
At Toyota " Under ideal conditions is never really explained "
Neither is Under extreme conditions like towing , heavy stop and go traffic , constant use of 4x4 low , heavy heating and cooling cycles etc
As you can see , many variables come into play and each Tacoma owner uses their truck differently . There can be no timeline for proper transmission servicing for each individual
truck until you take the variables of how you use your truck into consideration .
This is what I tell my customers . From there , my customers develope a baseline and have their transmission serviced according to how they utilize the truck .

A pan drop is exactly as described . The pan is removed for a contamination inspection , the filter is cut open for inspection and is replaced , the magnets are cleaned , then the pan is re-installed and filled back up with fresh fluid leaving 5 quarts of old fluid in the torque converter and cooling system . This is the proper procedure for performing a pan drop .
It is acceptable after the initial pan removal to add the remaining fluid once per month until all the fluid is new by simply removing the pan drain bolt and replacing the fluid . In " NO " way would I ever ever recommend draining the fluid without removing the pan on the first drain . Not with the all aluminum valve bodies we have in these trucks

 

Pics of filter and magnets.

 

The procedure to check the fluid in these trans seems like such a pita. If I do a pan drop, how much is required to fill back up? My truck shudders when cold for the first few miles, and has done this since day 1, and I’m now at 40k miles. Dealer wants $500 to change fluid, but the service writer didn’t even know there was a difference between a trans flush, and a pan/filter change. I’m more than capable doing this on my own, but I just want to make sure I get the whole warm up temp check procedure correct

 

If one were to find objectionable contamination; what do you recommend doing about it?
Does your approach differ for one that acts 'normal', versus one that doesn't?

 

There is a write up with pictures explaining the complete process here . Its very detailed
https://www.tacomaworld.com/threads/3rd-gen-automatic-transmission-fluid-level-check-diy.547455/

 

Hey Split !!
If we find exsessive contamination on the bottom of the pan covering the magnets and a plugged filter , we usually just install a new filter, fill the pan up with new fluid and leave the old fluid in the converter and cooling system .
We do not proceed with flushing the remaining fluid from the converter and cooling system

The approach ?
I will always test drive with the scanner connected, checking for codes before servicing to verify proper operation and converter lock up .
If we do find issues with operation , further diagnosis is completed before we service

From there if the customer requested a full fluid exchange , we would just change the oil in the pan and leave the old fluid in the converter and cooling system .
Its far too risky to perform a flush on a contaminated transmission with the super detergents new fluid comes with these days .
If however the bottom of the pan was clean , the magnets are clean and the filter is clean , we would proceed with a complete flush removing the remaining fluid from the converter and cooling system .
This is no different than the way we service any Toyota transmission . To be honest , other than Honda , we follow this guidline for all domestic services as well .
Hondas do not have transmission pans .
After the service is completed , a final road test is performed to re-verify operation before the vehicle is returned to the customer