2021 OR transmission shudder/surging at speed

Me 3

 

I think that rules out a mechanical problem...it is something in the ECU calibration. The ECU has cold engine and warm engine maps for many of the tables.

 

I didn't log speed for that first log. Here is that same section for the second log:

 

So, would you guys mind banding together with @BlueTaco4x4 to either open a case with corporate or possibly do some additional stuff to possibly get this addressed?


Of course, if we can kill it with a tune, that info will be made available.

 

The unfortunate problem is that even the best BT adapter is not fast enough to catch it. Fusion was only giving 1/sec data rates. It seems if we turn down the number of PIDs, it will log a bit faster, but this feels like a 10hz vib, at any speed. The wired vF logger is capturing something.


I did brain fart the last time that I was there with @BlueTaco4x4 and didn't try TS logging. That's on me, as the vF logger doesn't have any AT PIDs yet.


But, we do have logs from Fusion. There is only one that shows a bit of a TC dance, but the speeds are not steady to really know for sure.

 

Negative. A bad transmission or torque converter can/will behave much differently when it warms up and things start to expand.

Example: I had a 76 F150 with a C4 transmission. Tranny was perfectly fine for the first 5 mins of any drive, but after that...had to feather the gas, let it coast a little, feather the gas some more, let it coast a little, and then get on it in order to get it moving from a start. Clutch bands, especially bad ones, hate heat.

 

I have a feeling the shuddering you guys are feeling is a symptom of the engine under extreme load during break in . I dont have a 2021 to compare but a quality scanner or power graphing meter should help narrow down the issue when things start shuddering .
Oh Yah ! extreme load doesnt mean full throttle . It means your foot is hardly touching the gas pedal but the transmission is in the highest gear and your converter is locked up .
When that converter locks directly to the engine under extreme load , you can feel the slightest engine hiccup and slightest driveline vibration in the drivers seat .
Considering we see a similar post as this at least twice a week at Tacoma World , I have a feeling Toyota knows about the problem
Toyota programmers trying their best to make these trucks good on gas .
The result : you get to suffer with the drivability issues .

 

There was some of this happening on the 2019s. OVT made the special 1.05.1 tune to help with the shuddering / rumble strip feeling. I believe it helped in some cases.

I don't recall seeing much about this issue in the past year. But suddenly the 2021s seem to be popping up.


@OVTune 's suggestion was to first try changes to the Air Load Control maps. We did that with no success. I have not hit him up again on this, as the OP was intending to leave his Taco at the dealer. It ended up being two dealers, now with corporate saying they won't do anything until they get more reports.


Note that I personally felt this and it is shitty. Both @BlueTaco4x4 and I drove the same roads at the same speeds in my Taco. Nothing.

 

Had the Torque Conveter changed AT 92000 miles. ( 2016 Off Road) would shudder at about 35 to 40 MPH IN 3RD That cured it so far another 2000+ miles and all seem well

 

I have this same issue on my 2017 DBLB TRDOR 4x4. Did not experience this on my 2005 prerunner or my 2016 access cab 2wd.

I believe part of the problem to be the extra weight in this truck from the 4x4 system, double cab, truck is longer and heavier than my 2016 in general.

Currently I am sitting at the dealership waiting for the following TSBs to be done: 0077-16, ecm calibration shift feeling enhancements; 0062-18, stumble on throttle; and 0125-18 engine idle surge with steering input.

We'll see if any of these TSBs improve things. Will report back.

 

Just a not that this feeling is in all gears from about 25mph to as fast as the OP is going. Steady speeds and always about 10hz. It doesn't change with speed.

 

Nope, happens almost exclusively under light/no load. (for me at least) I do concede that it may be a software issue and not a physical one. But it's too soon to take an educated guess.

 

Note that TSB-0077-16 is an obsolete TSB. It will only give the 04B03 ECU update. The other two will give you the latest available, 04B04. All three do the same thing, update the ECU which is an improvement. They just reference different symptoms while applying the same fix.

 

Good point. And @tonered log shows engine speed oscillating while vehicle speed does not. Although it looks like the vehicle speed sensor does not have fine enough resolution to tell for sure.

 

Good info. Thanks for that. Hopefully the new software tune fixes these issues. The last owner of the vehicle never had any of them done. Had the ECU updates done to my 2016 but for slightly different reasons. Did not have the shuddering at low RPM and steady speed on the 16'.

Pretty damn annoying issues. Despite the annoyance, I won't trade to anything else though, at least not yet. Paid 30K for this truck and Vroom will give me 36K. Sweet deal, except for when you look at what it will cost to get into something else. Car market is nuts right now.

 

Does it do this with ECT mode on?

 

Interesting.

 

Had this issue with my 2012 Camry's 6 speed auto and it was the torque converter. TSB was issued and they covered it under warranty when I had over 100k miles on the clock. Torque converter replacement was the remedy. I guess if enough people have the issue and start to take it up the chain with Toyota NA, you'll see a TSB eventually.

 

With the speed of the vibes, the mass of the Taco probably damps it out with respect to speed changes?

You're welcome!

04B13 (similar to 04B04) was a big change for me. Note that the 2016 through 2018 ATs are the only ones that haven't seen a recent TSB update. The 2019 and early 2020 folks have been raving about TSB-0092-20 (ECU IDs 04B33 and 04B81). The MTs got a similar update and it is quite nice. So, keep your eyes peeled for that one.


It is difficult with small problems like that. It really messes with some folk and other don't mind it as much. You're right though, pickings are slim even with the crazy trade numbers these days. Same here though, the Taco is just good.

Damn. Good question! We didn't try it.

@BlueTaco4x4 , give ECT a test?

 

Great info!

Do you have the TSB number? It might give @BlueTaco4x4 a place to start?