Driveline shudder

So this is my first automatic Tacoma, coming out of a 5 speed. I've read all the transmission threads I can find, and my issue isn't with shifting. Generally speaking, for a slushbox, I think mine shifts fine and is generally fit for purpose.

My 'problem' is that I find that around 40-45mph (most notably), when the engine is turning ~1200rpm, if I dip into the throttle (no downshift) I find I get what feels like driveline shuddering, a bit of surging coupled with vibration: not electric toothbrush vibration, but almost a 'bouncing' for lack of a better description. It's actually rather hard to distinguish from the feeling of regular road imperfections/tire bounce, but it's definitely there. If I were to equate it to something similar in a manual, it feels a bit like when you're lugging the motor, but you'd have to really be at the point of rpm's dropping below idle to feel what I'm feeling in the auto (although it's nowhere near as extreme as what you'd get in that case)

The way around it is to just dip a little more quickly into the throttle and have it drop a gear, but I'm curious if this is common.

 

It appears to be something some of us are dealing with (I am included in the list). Went to dealer within the first 500 miles and was told it is a characteristic of the truck per Toyota. The service manager stated he felt that was Toyota's way of throwing a wet blanket on the fire and felt they were working on a solution. I would hope so. Some days it is worse than others.

Based on my understanding it is a programming issue with the torque converter locking and unlocking although I've also heard it has to do with the engine switching from the Atkinson cycle to Otto.

Like I said, it's seems better on some days and it can be annoying. Hopefully there are no long term detrimental effects. You can search the forum for fish-bite, lugging or missing/misfire and find others with the same symptoms you describe.

 

OVTune is the only thing that got rid of the shudder and clunking 2-1 downshift on my truck (2017).

 

Thanks for the info. If does very much feel to me like the torque converter locking/unlocking creating a bit of a surging feeling. Annoying, but not the end of the world. Fingers crossed for a software fix.

 

It is common, but on 16,17 and some 18s it was somewhat resolved by TSB.
Strange that you have it in 20 model.
Issue is related to torque converter being locked and "dead" throttle.
I used to let the pedal off and step on. This is unlocking the converter.

 

... interesting to read elsewhere that some people had luck with higher octane fuel, which of course would suggest it isn't the torque converter. I guess I'll give that shot and see what happens in the meantime.

 

I have a 2020 OR and haven’t had an issue, although I only have a couple of thousand miles on it at present.

 

Curious if anyone has heard anything about a further fix for this (from Toyota)?

 

Originally i had a minor shutter when braking to a stop...mostly on steep hills. After 1500 miles it all disappeared and all is good now. Definitely not the brakes...when i put the truck in neutral and hit the brakes it never was there. I suspected the torque converter as the issue, but that all went away once the truck broke in with more miles.

 

I’ve felt it. Same parameters and feeling you describe. It bogs there in my ‘20 OR. Weird programming, but otherwise I’ve enjoyed the driving characteristics of the truck overall.

 

How many miles do you have on the odometer? I had similar issues until I rolled over 2,000 miles.

The only remaining issue is downshifting while coasting.. creates an engine brake sometimes between 40 mph and 37 mph

 

3500 or so.

 

Is it the same with the a/c on or off?

 

Toyota headquarters Japan
call them
Address 1-4-18 Koraku, Bunkyo-ku, Tokyo 112-8701, Japan Phone (03) 3817-7111. BESbswy. BESbswy. Nagoya Office. Address 4-7-1 Meieki, Nakamura-ku, Nagoya City, Aichi Prefecture 450-8711, Japan Phone (052) 552-2111.

 

I don't know if I have experienced the same situation as others.
I have a 2020 SR and only twice in 3,000 miles (once this morning) I noticed a very noticeable vibration under power between 25-35 MPH. Today I was in "S" mode. I was going past the dealer later and when I mentioned it, he looked for TSBs and said nothing was ever submitted about vibrations. Feels almost like a torque converter.
It will only do it once while first starting out and both times the truck has not been driven a mile.

 

My 2019 does the same thing, pretty sure all these trucks do it. The dealer will say its normal.

 

my 2020 offroad does the same shudder 27500 miles

 

I did the same, took it to dealer at 5k and complained about the driveline vibration but they told me its just a normal characteristic of the truck. I've driven most modern trucks due to my line of work and I can confidently say I've never experienced it in any other truck. So I don't think its a "truck driving characteristic" but more so a "tacoma driving characteristic" if not an actual problem that toyota needs to address.

 

Just ask for Daisuke

 

This describes the exact problem that is happening with my truck. Ugh. 112K but I have not done AT transmission fluid replacement. I guess that's my next move.

When the engine is running 1000-1500 RPMs on light throttle application, there is a low-frequency ~4 bouncy vibrations per second in the driveline. It can happen at any speed, but mostly under 40 mph. There is also a higher frequency vibration that sometimes occurs around the same time and engine/trans conditions, which feels like hitting a rumble strip without the noise.

Does anyone have specific information about the supposed TSB fix for this issue? I would like to see what the dealer recommends if I take the truck in for service, and how to describe it so a TSB would be ordered.