2nd generation transmission shudder

I bought my Tacoma new on 2014. At about 55,000 miles it developed a shudder at 35-40 mph, at a steady throttle. I’m a motor head and the the problem aggravated me to no end. I tried flushing the transmission with WS fluid and the problem persisted. If I pulled the shift lever into 4th the shudder would go away. If I held the throttle steady with my right foot and tapped the brakes with my left the transmission would down shift and the shudder would go away only for the time it would take to upshift.
I bit the bullet and took it to a shop and they could find no error codes. They convinced me to change the torque converter. $1,300 later the shudder was still there. A different shop with a more experienced Toyota mechanic replaced the VVTi, Variable Valve Timing intake, solenoids. $120 later the truck runs like NEW.
IT IS NOT A TORQUE CONVERTER SHUDDER. Replace your VVTi for a faction of the cost to solve your shudder.

 

Thats interesting, and good to know!

 

Well, that is interesting indeed. As it so happens, I also have what I think is torque converter shudder, and I replaced one VVTi valve already due to a code, and I’m about to replace the second one due to a slight hesitation while accelerating. Will see if there’s any effect upon the shudder.

 

Does anybody think that this solution may help clear up a shudder from Stop-to-1st/1st-to-Stop (NOT park)? It seems to only act up during what I'd describe as a "rolling stop" and seems to trip itself up and shudder. It started about two weeks ago.

I'm getting a 200K service done today that will swap out all the fluids except the ATF and was hoping the rear diff change might clear it up, but if not i'll add this to my troubleshooting list.

 

I have had a shudder for the last 5 years. It doesn't happen all the time . It happens between 25-35 mph .A bit of a home grown mechanic myself , it has been driving me nuts. Tried everything that I could think of. Today I just went down to my local tranny guy and he quoted me 2k for the convertor or 4k for a rebuild tranny. I'm sure once I told him how many miles I had on my 2009 he just assuming its the convertor . How could you not think that , she has 450,000 on her . I take very good care of her. I am going try the solenoid just to see . It will be great if that is what it is. Thanks for the info .

 

Update
I changed out both VVT with NTK valves . The good news was it seemed to stop the shudder however the bad news is that its now throwing a engine cam timing code. I had no codes before . I drove the truck about 20 miles. No shudder. I even put it in situations where I know it would shudder. I am going to replace the NTK valves with Gates and see what I get . Its hard to tell what brand valve Toyota uses. The original valves don't have any name on it. I want to try these Gates before spending the money on valves from Toyota. They are $100 more expensive each through Toyota . I don't know if its my truck or just Toyota in general but I have noticed it does not like off brand parts on some things

 

I got my second VVTi valve replaced over the weekend, retrained the idle, and drove the truck to work today. I left it in D the entire time, did no manual shifting to 4... because the shudder is gone. I didn't believe it wasn't wishful thinking until the drive home, when I had plenty of 40 MPH gentle accelerations while the converter was in lockup, and it didn't do anything like it was doing before. I'm going to remain vigilant and see if this seems kinda permanent, but I'd certainly like to see some more datapoints on this from others going forward.

I wonder if @Dm93, @gearcruncher, or @TnShooter might want to weigh in on how this might be explained. Using the brake pedal tap test methodology, I was convinced my torque converter needed to be replaced. It was damned consistent for going on a few months.

 

That's very interesting, I can't say I've seen a VVT Solenoid cause a shudder before.
I've diagnosed plenty of torque converter shudder, pretty easy on most vehicles watching TCC slip with a graphing scanner and looking for spikes when the shudder occurs.

 

I can’t explain it.
Maybe the “bad” VVTi had the engine lugging cause a shudder effect?
But the VVTi should not affect the transmission torque converter.

 

It's easy to explain .
It feels like a torque converter shudder from the drivers seat so it must be a converter shudder
That being said , most people go for the converter issue before taking the time to do the extra diagnostics .
Yes , when you tap the brake pedal in drive the chugging goes away, so it must be a converter shudder , however,
This is only half of the diagnostics .
What is causing the truck to chug when the converter is locked ?
99 percent of shudder complaints are caused by a rough running engine .
When a converter clutch shudders , the actual shudder only occurs for 1/2 a second in most cases
If you feel constant chugging while in drive , it's better to look at engine diagnostics first

 

The only theory I've come up with so far is that at 40mph with the converter locked, RPMs drop to about 1100. It takes a good bit of pressure on the gas pedal before it will drop out of lockup, so while locked the engine is about in its max lugging situation - much like keeping your manual trans in 5th or 6th gear at a lowish RPM and trying to accelerate. The 1100 RPM isn't low enough to be as much of a lug as you can manage with a manual, but perhaps that particular loading situation sets up an odd situation with the ECU and the valve timing where it begins to oscillate and feels exactly like a TC shudder. It would obviously involve some particular wear characteristics of the oil control valves if new ones fix it.

This theory doesn't feel entirely right, though. I would expect to be able to set up the conditions in 4th gear as well, maybe on a slight uphill at the same RPM, and cause the same shudder. But who knows, maybe there's some code in the ECU that says "if ($tcLockup == 'true') {do something different with valve timing}".

I'll keep an eye on things and report back if anything changes. @Retired FROG and @BrianW09, please do the same should the shudder return on your Tacos. Can't wait to hear from the next person who tries the valve replacement when they have a shudder.

 

This is awesome. Thank you for sharing. I've had the same shudder for years now at the same 35-40mph.

 

Did you go with aftermarket or oem?

 

OEM. I figured if the first set made it almost 120K miles, that was good enough for me.

 

I'm going to try Duralast. I normally go with OEM, but if they don't work, I can return them. They come with the lifetime warranty, so if they have issues in a couple years, I can still get them replaced for free.

 

We had an FJ Cruiser with the same problem. Trans was replaced under warranty and that solved it.

 

On my 07 6cyl i did the 18qt flush at 60k.......had a shudder that seemed it was the torque converter.......never got rid of it.

 

My 15 has 128K and no shudder. Just curious if y’all’s engines are dirty with deposits. Some people had to replace the VVT screens due to them getting clogged. My front end looks like this. I’m just guessing here.

 

Mine may have more wear than some, and I think you've got the right general idea but I don't think it's a clog that's the mechanism at work here. I did pull the bank 1 filter screen before replacing the associated control valve and it was completely unobstructed. What I've been thinking may be going on is that the piston and the bore for the valve get some wear and oil starts to leak beyond what it should. Then some combination of drop of engine RPM when the converter locks, ECU software deciding what to set the oil control valve at, and the converter locking logic enters a feedback loop where the ECU commands the converter lock on and off rapidly. I would further speculate that this also has something to do with a slightly worn torque converter, such that replacing either the converter or the oil control valves can alleviate the shudder.

This does assume it's even possible to command the converter on and off quickly enough, and that it can respond just as quickly (a few times a second, I would think) to cause the shudder. I could be completely full of it but this is what I've come up with so far.

It's been three days of commute traffic so lots of times where the speed/load conditions were just right and still zero shudder. I do wish my valves didn't get destroyed during removal, I'd be putting them back in and probing a few signals or monitoring the converter lock PID to try to isolate this. Alas...

 

Damn you sound like a mad scientist. Keep us posted what happens.