Low speed clunk

This might be on here somewhere already but I haven't been able to find a thread on it. Note: this is my first truck in 25 years. Picked up a 2021 sr5 CM TRD OR. When driving around town (anywhere under let's says 35mph or so) after letting off the gas, when I get back on the throttle I can get a pretty good clunk right before accelerating. Almost like it's searching for the right gear or it's in way too low of a gear.

If I maintain JUST a bit of throttle engaged then it does not happen. Its when I have completely let off to coast and then get back on no matter how gently I do it.
It shifts crisp and smoothly from a stop and even after this clunk. Wondering if this is an issue or just the nature of the transmission. All thoughts appreciated.

Thank you!

 

How many miles on vehicle? Ujoint could be a thought.

 

26.5K miles on it currently. I've put about 1k on it so far.

 

I am not sure if this is the exact same issue but my truck drove weird for a few miles. I bought mine used and had to reset the ECU which programs the truck to drive like the previous owner. Since resetting the ECU the truck has been smooth.

 

Interesting, I will bring it up with my local shop. What do you mean by driving weird?

 

It is hard to describe, but at low speeds my truck used to hold gears for long periods of time, and when I used the throttle it almost held in place then grabbed a gear and started driving.

 

I gotcha. Yeah this seems to almost be the opposite. It appears to be shifting to or staying in too high of a gear with very low RPMs. Then the clunk happens when getting back on the gas. Once throttle is re-engaged everything is fine and smooth

 

Thanks for the input. Looking into all options/causes at this point as I really like the truck otherwise.

 

Changing the fluid may fix it just a drain and fill with WS. My trans dues this I think its shifting gears maybe fluid cold but one day after changing the fluid it seems fine we will see in a couple more weeks. These trans don't like cold fluid.

 

Interesting, thanks for the info. Mine clunks even when warmed up fully. It's like it has shifted into too high of a gear or just doesn't like the engagement of the throttle after going to a coast at low speeds. If I stay just barely on the throttle it doesn't happen qhen I go to accelerate. Only from coast to gas.

 

My trans dues the same we will see in a few weeks I think the dif (Red Line) change did help. I wouldn't be to stressed over it my trans did this from the dealer.

Going down a hill off the throttle will make the trans down shift and clunk I think. Going up hill in traffic 5 mph it will down shift and can do this. If my memory is correct.

 

I searched around the other forums and it could also be low transmission fluid. I am going to take my truck in when I come back from school, but I'd love to know what your dealer says @Upstater13.

 

Will let you know what they say once I can get to shop.

 

Is it just a little bit of rear end play? Like there is reverse pressure on the rear end gears because you let off the throttle then when you get back on the throttle the gears go from the engine slowing the truck down to the engine pushing the truck faster and that little bit of play in the gears shows up as a light clunk? Mine has done this from new. And alot of other trucks I have drove do this.

I also try to feather the throttle slowly and clunk won't happen.

 

This sure sounds like exactly what is happening (I just couldn't word it as well).

 

43,000 miles on my 2019 and mine does the same. Changed the transmission fluid, front/rear differential fluid, and transfer case fluid trying to solve this, and it still occurs. Just the truck, sounds like they all are this way. Hope to get hundreds of thousands of clunky miles on mine.

 

Did you buy it new? Did you try disconnecting the battery?

 

I also think it's more noticeable in out trucks because of the gearing is lower, or the driveshafts spins faster on our trucks than other brands because their more geared for MPG.

 

This^^^…2018 with 72xxx miles. Had all driveline fluids changed @70k. Clunks every now and then…been doing it since I’ve had the truck.

 

Tundra transmissions have what is called Artificial Intelligence-Shift Control, which is built into the ECM. It collects data from various sensors and the ECM attempts to predict road conditions and driver intention, adjusting the shift pattern so it shifts smoothly. Point being, check your fluids and if they are OK, keep driving for a while so the truck can learn your driving habbits and adjust the shift pattern accordingly.

I had the same problem with my Tundra (bought used) and it went away after a couple of months. Shifts smooth as butter now.

FWIW, you can disable AI shift control by putting your truck in "S" mode versus D.

 

Weird, mine doesn't clunk. There have been a few people on here that have had new rear ends put into theirs. Worth having the service advisor at your dealership take it for a drive while it's under warranty.

 

Mine does the same thing and has since new. Driveline lash compounded is my thought. When I get my next oil change the shop has agreed to allow me to due an under body inspection and the plan it to put the truck on the lift in park but brakes releases. One of us will hold one wheel while the other tries to rotate the other noting where the rotation play is.

 

Did you ever reset the ECU for that or just give it time?

 

Thanks for the info. Will definitely have them take a look. I know there are entire threads on it but I'm going back and forth on extending the bumper to bumper or not. I've only got about a month or so to decide..

 

Just gave it time.

 

When I bought mine I noticed harder shifting than I was used to. I swapped the fluid and it continued to downshift and upshift hard in lower gears.

After 500 miles of "around town" driving it was noticeably smoother, and now after 3,000 miles it shifts great.

My guess is that me and the previous owner have very different driving styles.

 

Bought this truck with 40K. Previous owner installed bags so it was a towing truck. My Previous tundra had this happen maybe 3 times.

I occasionally have this. Usually hitting the gas harder then normal on a coast down into a red light.
Son had this happen when he drove it. Leads me to think the ECM idea is a good one.

My question is - Has anyone had major problems down the road from this noise?