Feels like I have a transmission shudder- any advice?

I bought myself a new to me 2009 tacoma, v6 automatic about a month ago. It has 180K on it, but has a new frame, I bought from the original owner, and it seemed to be in great shape. Plus I was not about to take on the payment of a new truck, so it seemed like a great buy. I noticed this past weekend that the truck vibrates a bit when I am light on the throttle, between 42 MPH and 50 MPH or so. If I let off the gas it stops, or if I give it heavy gas it stops. I'm no expert, but based on some quick reading it sounds like it is a transmission shudder? Is there anything else that it could be other than this? The prior owner gave me a stack of paperwork, receipts, and cutout carboard tags from every oil filter box he has put in the truck since 2011. On one of the carboard tags from Feb 2020, at 150K miles, he wrote on it that he did a transmission fluid flush.

 

Check your U-joints and carrier bearing

 

Check all the ujoints first and carrier bearing.

 

Drive it in 4th, if it disappears it's flex lock up shudder. There are a myriad of causes for it.

 

Thanks for the response. Easy way to check these? As far as noise goes, there are no strange noises coming from the truck as I drive it.

 

Put it in 4th gear and see if it goes away.

You can also do a converter shudder test.
This is a excellent test post by member Gearcruncher here on TW.

https://www.tacomaworld.com/threads...th-pics-for-second-gen-4-liter-trucks.289913/

Here is how you can test for a converter shudder from home .

Allow the truck to warm to operating temp . Your converter will not lock up when its cold .
Place the shifter into the overdrive position and drive until you feel the converter shudder .
Once you begin feeling the shudder , use the " Brake Tap Test " to see if the shuddering goes away .

As soon as you feel the shudder , use your left foot and gently tap the brake pedal about 1/4 inch down but leave your right foot steady on the gas pedal .
The idea here is not actually hitting the brakes but manipulating the brake switch . Manipulating the brake switch tells the computer that you are coming to a stop . Your computer will then command the converter clutch to the off position for a couple of seconds . When the converter turns off , your shudder is going to go away for a brief moment .
Because , you only tapped the brake pedal to manipulate the brake switch and you still have your right foot steady on the gas pedal , the computer in your truck will then command the torque converter to re-apply the locking clutch and your shudder will instantly return .

 

Unless it's completely wasted and obvious, you have to remove the driveshaft to properly check them.

 

Crawl under it and get a good look first, the first sign of U-joints being bad is dry (lack of grease) and rust coming from them. Carrier bearing, grab the driveshaft and see if you have any wiggle near it.

 

I'm glad you mentioned that. When driving yesterday I did try using the individual gears instead of "drive", and the vibration was in fact gone when I did this. I tried multiple times and the truck did not vibrate at all. Once i put it back into drive versus individual gears, the shudder resumed.

 

It is probably converter shudder.
You could do a drain and fill and ad LubeGuard and hope the problem goes away.

 

Flex lockup...partial PWM modulated lockup.
Could be:
-fluid
-valve body wear
-solenoid performance
-TCC clutch condition
-transmission mounts
-engine stumble
-ECM
-sensors
-etc...

IMO, atf ws is 60,000 mile max...
Hate to see you start throwing money at it without a thorough diagnostic, though.

 

The previous owner did do a tranny flush, but was the correct amounts of transmission fluid replaced. It could’ve been low when he started. I would look up the process to check and check that out.

 

Did you receive the service records from the original owner? If so, check and see when/if the transmission was serviced. If you’ve got no indication the fluid was ever changed, then @TnShooter is right on the money (as per usual), and it’s a good idea to do this regardless of whether the converter is your fundamental issue or not.

If it was changed, you can try adding the LubeGard Shudder Fixx product. It’s only 2 ounces so it won’t be a problem to add as long as your fluid isn’t already overfull.

 

IMO, people who wait until 150,000 to do this, are not big believers in timely and regular maintenance. They're hoping it will fix something...

 

Check out this thread. I had a similar problem like this for my 2010 and something cheap to try out is putting in Lubegard Instant Shudder fix and and bottle of Lubegard ATM protectant. I've driven the truck for about 100 miles now and my shudder problem hasn't came back yet.

https://www.tacomaworld.com/threads/jerky-acceleration.704719/

 

It's entirely possible that I'm a hypochondriac, but on the way into work today I had to take the truck and I'm pretty sure when accelerating from about 42 MPH I was feeling a shudder. A tap of the brake and it stopped. Dagnabbit!

 

changed my trans fluid at about 250k for first time due to shudder
I have towed a camper for a few 1000 miles and drove it hard mostly but not much stop and go highway BS

fluid was not burnt or smelled bad, tuck did high RPM with full throttle stall test in D finally so i knwe then it was fluid time.

Shudder can be a pain to find.
carrier mount it self isnt set right, dropping it a half inch did wonders for me
any u joint bind, make it shudder
full load take off, flexes the rear leafs and shudder be there unless you get better springs or learn to roll on the throttle instead on step on it.

 

I tried this and the shudder did go away when tapping the brake, and did return when I let off the break. Sounds like I have a big issue?

 

Not necessarily. Read up and try a thing or two. No need to loose the faith yet!

 

UPDATES:
The shudder happens in 2WD and 4WD. If I keep on the gas and tap the brake with my left foot, the shudder goes away; as soon as I let off the brake, the shudder returns. I spoke with the prior owner and he did a drain and refill on the transmission fluid at 150K miles because he felt the shudder, but he did not do a full flush. He also said that he noticed that the shudder would come and go.... it would have been nice if he was honest and told me this before I bought it.

Any advice? Based on this info, is it possible that the shudder is something other than the converter?