Another 3rd Gen torque converter issue?

Alright, before we get started, I'll provide some context. It's a little bit of a story, I appreciate your time in advance.

Firstly, I’ve seen so many threads about torque converter shudder for these third gens. I’m aware it’s somewhat of an issue, but the solutions are a mix bag. My goal here is to see if I’m on the right track, and if any of y’all have any suggestions or advice. My limited warranty is almost over..

I am a software engineer, and I am very analytical, so I will try to be as detailed as I can be. I know in order for y’all to help, you need facts. Sorry if this is overkill, but it’s been bothering the hell out of me.

Recently, I've had this shudder that I notice from my 2018, TRD OR, AT. Truck has 58,XXX Miles on the ODO. issue started roughly 500 miles ago.

When the shudder occurs, I feel it right under the driver and passenger seat, and towards the front of the truck. It’s almost as if.. the rpm’s are too low, and it’s bogging down. I would say it’s not as intense as riding over speed strips, as some has compared it to, but instead a subtle choke for power.

Anyway, this issue is consistent, occurring 100% of each time the truck is driven.

// Issue example: Truck powered on, warmed up (at normal operating temperature)

While traveling down the road, if I encounter a slight to moderate hill, while maintaining throttle, the speed begins to drop, rpm’s begin to drop and unless I force force acceleration it begins to shudder and then forces itself to downshift. The actual shift is not overly clunky or hard. It’s also not buttery smooth.

I’ve also noticed that when I am accelerating (going straight, no turns, no inclines) 1-3 gear are smooth, when it hits 4-5 the rpm’s again drop, and it’s almost like once again everything is bogging down. A more subtle shudder is noticed at this point. Usually around 45-50mph.

// Additional details
- Does not feel feel like it’s misfiring in idle
- Does not shudder upon general acceleration
- Shudder not noticed below 30, even going uphill.
- No leaks or any other evident signs of problems
- No engine modifications
- Lifted, 2.5, on 265/75/16 Nitto ridge grapplers (condition is like new).

// Recent changes prior to noticing.

- Just prior, got a full tank of gas (a day before it started)
- Within 500 miles prior, replaced shocks and struts
- Within 500 miles prior , did the ECGS bushing

Also, I have noticed a faint rubber burning smell from the engine area, but can never track it down. Also occurred roughly 500 miles before issue started.

// What I’ve done so far
(Much of this is thanks to y’all’s advice when I first started trying to find out what I was experiencing)
- Balanced tires
- Had alignment done
- Had shop that installed suspension review everything, had another shop double check their work
- Added “heet” to my gas tank, in the event I got bad gas
- Took fuel samples, no bad gas apparent.

// Current situation

I said screw it, I’ll gladly pay the 150-500 (or whatever) Toyota charges for a full inspection / diagnostics.

Service manager and master tech advised I allow the tech to drive the truck for a few days, to his house and back. I agreed, because I know the issue is able to be duplicated.

// Day one of tech driving the truck: CND (cannot duplicate)

I’m very much annoyed at this point, because I know it’s occurring. However, I’ll give him a few days, there’s no way it won’t be noticed.

Service manager advised they are going to use a computer to monitor everything, check ATF fluid, take more gas samples. They apparently inspected the draft shaft, ujoints, and everything checked out. UCA, LCA, and other suspension components also inspected and are fine. The induction system will also be inspected.

// Day two, current day: Tech drove truck home, and will drive it over thanksgiving and I’ll get a call Friday.

To clarify, I am almost certain, based upon principal of isolation, that these are tall tail signs of a failing TC.

I am slightly worried, because I’ve read countless experiences, just like mine, in which the tech considers that “normal” and therefore they will be unwilling to replace the TC, or transmission (worst case). Which means for me.. as it continues to wear, I may end up trashing the valve body.. I’ll be out of warranty and most likely paying 6k for a new transmission..


So idk y’all, what do you think? Anything else to check for? Suggest? They claim they have an open case with Toyota, and will be reporting their findings. Whether that helps or it doesn’t is to be determined.

Any advice, suggestions or tips are welcome.

Oh.. and I fully plan on driving with the tech to assure the duplication is observed as well, I just figured it was so apparent… they couldn’t mistake it. I’ve driven other Tacoma’s, none do this.

 

A significant number of trucks have done this since new (including mine). Lots of discussion within the forum.

If it meets these typical symptoms, it's probably going to be considered normal:
Speed approx 40-50mph
Rpm less than 2000
Light acceleration (or incline).
Feels like traveling over slightly bumpy road.

The dealer will most likely not find anything wrong and will say it's normal for the Atkinson engine or TC flex lockup. If their computer doesn't show anything odd going on, they won't act.

If you're near 60k, I'd have them do a drain/fill on the tranny fluid while it's there on the chance it helps.

Good luck. Interested to hear what you find out.

 

Allowing the tech to use as his daily driver is a pretty bold move.

 

You said it doesn’t feel like it’s misfiring at idle. Maybe it is. Something about cylinder three perhaps. Don’t know the deets on problem

 

Is there a cliff notes for the original post?

 

There's a lot of info in there but OP was thorough.

I've had my 2021 Sport tuned with OTT 8.0 since May of this year and I'm lovin' how the transmission operates now.

I'm interested in the outcome as well. I would hesitate to let any technician take my truck home to check out the problem--Bold Indeed!

 

I get Toyota's (and other makes) in the shop with TC shudder all the time. Depending how severe it is, a couple of drain and refills of the trans (using the OE fluid) fixes the issue 95% of the time.

 

Very nice detailed write up.

As you say it occurs 100% on every drive too bad the tech couldn't just ride with you for 15 minutes.

I would start off with a fluid change using OEM fluid.

Subbed for answer, good luck and keep us posted.

 

Only way to mitigate it- tune it. It is not failing..and change the fluid

 

Appreciate y’all chiming in here.

A few things..

Many advise there shudder is around 45-50 or so. While I do notice it bogging down, I don’t have the rubble strips per se. In my case, the 55-65 is the much more notable milestone of occurrence. Even then, less rumble strips, more of a bumpy road for sure. Perhaps it’s the same difference.

I’ve contemplated tuning at this point, but I hear that won’t help

I’ve contemplated the peddle commander, and hear me out, because it’s simply changing the throttle mapping (not shift points) so, in theory, I shouldn’t have to press as hard at those higher speeds for a downshift and perhaps it’ll be less prone to shudder? Example: Maintaining at 60, slight hill approaching, instead of me having to press harder and harder with no response.. I can lightly press, it’ll shift and just.. go?

However, I’m not certain that will actually help lol.

Lastly, let’s talk about the tech taking the truck home. I can understand why that’s a bit… concerning, I’d like to hear why y’all think so as well.

Not to sound… creepy, but I have an AirTag on my keys. The truck has gone to their house, and has been there. No joy rides that I’ve noticed lol.

Only thing that somewhat pisses me off.. is that the service manager said “we are checking the AFT right now” and when I checked it on the map… it was at a parts store, nowhere near the dealership. So…….. that’s annoying.

Anyway, thanks for y’all’s input.

 

Change. The. Fluid. First.

 

Absolutely. They checked the fluid to make sure I wasn’t low, I’m unsure what they actually did to assure that lol. Other than warning it up, removing the plug and seeing if anything comes out.

 

When you say it’s not failing, let me ask you what makes you believe that?

I only ask, not to be argumentative, but instead for data gathering purposes.

Mainly, I experienced the gear holding and hunting prior. There was never shudder. Therefore, the tune may have helped with that. However, I do not see the tune specifically telling TC engagement. Unless you know something I don’t, hence why I’m seeking clarity. Lol

 

I had it driving traffic in my hilly area 45k miles ago.
It happens due to dead pedal (not enough throttle at given speed), low rpms(no torque), long downshift points in 5,6 and tc being locked.
Tune will help you to overcome this + add a few ponies so you can conquer that hill in 6th.

 

And torque converter starts locking in 3rd. If it is failing, you should see issues in low speeds/gears

 

Remember the TC lock up clutch is a friction material that sees a lot of slippage. The fluid has additives for friction modification that actually wear out. Keeping fresh fluid in there goes a long way to keeping smooth converter operation.

 

I plan on doing the “brake” test.

Where when the shudder starts, you light tap the brake with your other food, while holding gas, and it should “trick” the system into thinking you’re coming to a stop, unlocking the TC. If the shudder stops during this test, it’s evident of TC issues, yeah?

As others have mentioned, I’m going to drain and fill with new fluid regardless, I’m just unsure how that’ll solve the problem. I mean, it’s under 60k. It’s not beat up. Some don’t ever change the fluid and are fine.

 

Ah, I didn’t know the additives wear out! That’s good to know. Gives me… hope lol.

A guy actually recommended this.. “little green bottle that Ford sells” to help add friction. Unsure if that would help as well.

 

Sounds like torque converter shudder.. I have an 09 tacoma that had zero issues.. i change the fluid regularly,drain and fill every 15k.. so we have BG synthetic fluid at work.. it’s good fluid and compatible with WS..so I decided to flush it at around 100k…the next morning when it was cold that truck bounced all the way to work… it was terrible… flushed it back out with WS fluid and it is smooth as glass

 

The struggle is real.

In my case, a drain and fill may help? Or should I flush?