Weird shuddering on brand new Tacoma when cruising down highway or climbing up hill

Hello ya'll. Got a 2023 LB. To start, I have a OTT tune on my truck. Put it on at about 3k miles. I am getting a weird slight shudder when my truck is cruising down the highway and sitting in 1500 RPM's range and also when climbing up hill and it's sitting around 2700 RPM's. It's minimal but it's not a smooth ride, definitely seems like it's the tranny trying to do something where the standard tune would do it's gear hunting. I reached out to OTT and they said maybe top off tranny fluid or report it to my tuner so they can log it... I was also informed by some others that this is typical behavior of a new Tacoma if the transmission fluid is not topped off. So I reached out to Toyota to schedule a session and over the phone, the lady was of no help saying they wouldn't top it off for me. "The truck is a sealed transmission and that's probably not the issue but we'll schedule you a session with our advisors in the service department. It's the transmission learning your driving." Truck is just over 5600k miles. Any ideas? Common behavior? Ditch the tune?

Disclaimer, yes I have searched, yes I haven't found a solid answer and that is why I am using the forum!

 

Welcome to the suck

 

Myself and a number of others have experienced the same thing. I also have a tune. U likely will find if u put the transmission in S4 which prevents 5th and 6th gear from being used, it doesnt usually occur. If it was a normal characteristic of the truck they should all do it. Usually when a dealer says that its usually because the manyfacturer doesnt know whats causing it and/or has fugured out a fix for it.

Myself and a few others on here have found it less noticable when using higher octane fuel.

Ive come to learn recently that 3.5 V6 in the current Tacoma came from the Lexus lineup and like a lot of of other Lexus models the recommended 91 octane when it was in the Lexus models.

 

That sounds like what any manual transmission does, when th RPM are too low. IE: truck is in 2nd gear at 6mph and should be in first.

 

is my understanding correct that you did not have the shudder for the first 3K miles, before you installed the tune?

if that's the case then yes, i would consider ditching the tune but not until i verified the fluid level in the tranny was correct and, not until i tried another brand/octane of fuel.

 

Why some of these trucks develop that shudder is kind of a mystery. A buddies truck had it till the time he unloaded it. I thought mine had some very early on while under 1k miles, but it disappeared, never to return. Truck runs great on 87, always has.

 

Which trottle settings is your tune?

 

If I recall correctly the Lexus versions are about 300-306 hp. Assuming the compression and cam profiles are the same with the FSE/FKS versions I would venture to say it's all in the tuning (probably why yours runs better with the premium).

The Highlander was using the FKS version as well (the 2023 has an I4 turbo, 310lb ft @ 1700 rpm!) and was rated slightly higher @ 295hp on regular fuel.

 

He was able to run in current conditions on oem "tune". He stated the gear would drop.
Op symptoms are related to throttle limits and probably some other tune parameters.
Definitely not fluid level issue

 

AT shudder is most likely the torque converter locking up. Usually caused by low AT fluid level, a common problem on these trucks from the factory. If the truck is under warranty, get AT fluid level checked and filled to spec. Otherwise, add 1 tube of Lubegard Instant Shudder Fix in the AT fluid fill (2WD / 4WD). It should eliminate the shudder/lockup. If it's "fixed", your TC is good... if not... $$$$ problem$. Regardless... do a level check as described in the 3rd Gen AT Fluid Level Check DIY thread. Shudder Fix is a "diagnostic tool", according to the MFG.

My 2017 DCSB 4WD Offroad got this problem at 100K. 1 tube of Shudder Fix made it go away until I can do a drain, drop the pan, install new filter/gasket/washer kit and refill... I will add a tube of Shudder Fix to the fluid when I do that job.

Also, FYI, the poison warning on the Shudder Fix tube is legit. It is a skin irritant. DO NOT let it get in your eyes, nose, mouth. Wear gloves and goggles for the quick fix. I got a little fluid under my shirt cuff and waited a bit to wash it off... mistake. It's not as caustic as brake fluid, but it does penetrate the skin. And you will most likely get some cuts and scrapes on your hands due to the remote location of the AT fill port.

 

Please don't confuse OP.
3rd gen tranny torque converter is designed to lock up and maintain locked till the death.
Tunes are dealing with this by increasing the production of engine torque , modifying downshift point and torque converter unlocking points. Op need to go back to the tuner and don't waste time on checking fluid level.

 

OK Vlady, póg mo thóin.

 

Just saw this posted on a Tundra fb group. Is this something that is gonna plague the new Tundras as well.

"I have 2022 Hybrid 1794 edition with TRD package. 7500 miles. It has a new transmission and rear dif. Both were changed by the dealer while trying to solve a vibration/ shutter that happens when accelerating without punching the gas. Most noticeable when going between 35 and 55. The hybrid maxs out, then the turbo kicks in. This is when it happens.
The dealership finally came back and said "that's just the way these trucks are". Has anyone else had this issue? Has anyone solved this issue?"

 

Yes, we have...


Unless you are SCARED OF DOCTOR TRANNY... give it a try!

 

Welcome to the Tacoma, it will last forever and evidently bug the shit out of you the whole time. Or so it appears from this forum.

 

I would never tune mine.

 

That's the point. My truck is bone stock like many others out there, runs very well on 87, worse on 93. It has no shudder. Why shouldn't all these trucks be the same? There's got to be some reason. Hasn't anyone question why?

 

This particular case of shudder is induced by the tune.

 

Lite, and Spicy ECT.

Personally, I feel like I did enough research to not hear this was happening with tunes on so I was confident on putting it on. I am going to remove it and see what the OEM tune does. Then go from there. It was bad today climbing over the hill...so damn annoying.

I can't say for sure if it wasn't happening before the tune, I do remember thinking that the truck felt like it was behaving weird on the freeway. So much so that I felt like a tune might "fix" how bad it felt driving.