Shudder on deceleration?

OVTune-- fine , but WHY should I have to pay for a fix for this "mis-engineering"

 

Try coming to a stop with your hands off of the wheel -- I have tested this out (when safe) about a dozen times -- never got the hard downshifts when letting loose of the wheel! Try it out in a no/low traffic area -- you will see!

 

I used to notice some shudder from the rear end when decelerating, usually above 40MPH, then it would go away. I'm not noticing it anymore. Truck's got just under 8000 miles on it now. Maybe the drums needed some set-in? I DO occasionally notice the transmission downshift, but wouldn't say it ever shudders much.

 

Okay; I remember you now...

 

Great thing is that -I like the everything else about the truck aside from this one quirk!!

 

Split .
You have been around long enough ..... The converter doesnt come on when the trans is cold .
Take your truck for a test drive cold to see if the issue continues . If the problem is still there , its got nothing to do with the converter locking feature and we can start looking at other possibilities

 

I don't have the problem; but have not seen where this problem is limited to cold condition only.

Full lock-up prohibited when;
-ATF below 104F
-coolant below 158F
-accelerator is lifted
-stop switch is activated
-shift range between 1 and 3

I'm talking about the flex lock-up during deceleration strategy Toyota uses, though.
https://www.toyotaguru.us/camry-repair/flex-lockup-clutch-control-1.html

Flex lock-up is active in 2,3,4,5,6...this goes against the full lock-up prohibitions. Control would end between the 2-1 shift. Maybe it's not; it has a 3 second minimum malfunction threshold...
You have to brake or lift to decelerate...this goes against the full lock-up prohibitions.
I purpose flex lock-up doesn't follow the same rules as full lock-up.

 

Thanks for the schooling split .
For the OP , Do you have the problem when the truck is cold ?

 

Is the shudder there when braking and not braking? My 2017 had this problem off the lot which they kept dismissing, fiance even thought I was crazy. I lifted my truck and did the ECGS bushing swap but was actually worse. Finally shimmed the rear and problem free now. My problem was the driveline angle even stock.

I'm quite sure the stock driveline angle is a known problem from Toyota. Look under a new off road they actually shim the rear from factory. I've asked a few dealers for the degree doesn't show up on their parts breakdown. With a rear 3 leaf aal I have a 2 degree shim.

 

Image of a late 2017 stock off road I snapped you can see the shim

 

I don't claim to know more about this than anyone else.
You have probably forgotten more about transmissions that I could ever hope to know.
I'm just saying, from what I do know, the possibilities exist.

I think you and I agree, the AB60 is as close as we can get to how the AC60 functions.

Here's a link to a trans tech using a Yokogawa DL850V Scopecorder and Xviewer software to monitor solenoid functions on a AB60 transmission.
https://certifiedtransmission.wordp...-driving-drafted-to-dyno-testing-development/
It was fascinating to learn that solenoid cycles don't follow the traditional on/off function from 'the charts'; they can have partial duty cycles throughout the shift range. As good as OVtune might be, unless he is using these higher functioning tools to diagnose the transmission logic, he's kind of guessing, IMO.

Here's a link to Toledo Trans Kit seminar covering the AB60.
https://www.scribd.com/doc/295779954/A760-AB60-Comparison
Things I find worthy of mention are:
-When the output speed sensor fails, up-shift to 5th and 6th are prohibited, along with AI-shift and flex lock-up. There was a fellow here recently, who had this exact condition; from the service manual, you would never know it. I could only surmise, a possible SL1 failure from what the service manual provided. I think you were the last one to post in that thread...
-The operation of flex lock-up is present during deceleration; in case the Camry article I referenced previously, doesn't sit well.
-The 'true' function of the two atf temp sensors in somewhat layman terms. Conventional wisdom is, one monitors the converter and one monitors the pan. While that may be true, it was never explained why.
-Viscosity comparison graph of ATF-WS vs ATF Type T-IV

I guess what I'm really saying is, "shits complicated yo".

 

Cold, warm...either or.

 

Thanks for throwing this info together Split !! . I dont have the time for the research anymore .
Back in the early 90,s up to about 2005 , I was a moderator on a " universal vehicle " help forum and i was paid for my diagnostic troubleshooting on almost all transmissions functioning at that time and before hand . People actually paid me well to help diagnose their transmission issues
Since then , the internet has become more specific such as Tacoma World or Tundra talk etc etc .There is a forum for every vehicle made now
The only reason I am here is because I own a Tacoma
When a member asks a transmission question on Tacoma World , I always begin with basic questions and try hard as hell not to overcomplicate the answers
You are 100% correct !! Ever since Pulse Width modulation came about , it has made things much more complicated .
The boys over at OV tune truly have their work cut out for them and I applaud the work they have accomplished thus far .
Any proper diagnsotics whatsoever always begins with the connection of a Techstream scanner .
I will check the video out on my days off
EDIT : I havnt test driven a 17 model Tacoma yet . With this said , I get info from other top members such as yourself who have more free time to research .
Please keep doing what you do
Got a question for you Split ? In the manual , is there any information regarding squawk control ? I havnt had time to look for this on the AC60 series transmissions .

 

I have a 17 OR DCSB with 2,000 miles on it.

It has shuddered from the rear peridically when coming to a stop since the day i picked it up with 8 miles on it.

Dealer looked at it and said it's operating as intended.