Transmission clunk when cold

I just got a 2015 with 113k. When I hit around 30mph there's a definite kick when it shifts and then after a bout five minutes there's a bit of a clunk when I take my foot off the gas and start to slow down. This only happens when it's cold, such s first run in the morning or if it's been sitting a while.

Any ideas on what's happening? My wife's 2002 4runner also has a hard shift when starting out cold and so does my Sienna, but the Tacoma is much more pronounced, especially the clunk on slowing down.

Thanks.

 

Had the U joints checked?

 

This is very frustrating. I've had it to the dealer three times and they say they can't replicate the problem and that the vehicle is operating normally. Is this normal? When starting out when it's cold, it goes into reverse and drive without a problem. When it shifts into 3rd there's a noticeable thud, and then about 10-15 seconds later they're' a more pronounced thud. The first time I took it to the dealer they said they couldn't replicate the problem and everything seemed to be fine. The second time I went for a ride with the tech and there was just a soft thud that he didn't notice. Still, he recommended a flush, which I did, but it hasn't made a difference. The third time they said they couldn't replicate it and wait until it gets worse. I also did an ECU reset. The problem seemed to go away, but returned after a few days. This morning, in addition to the usual two thuds, there were two more thuds that didn't seem to be connected to gear shifts. After that there was no problem.

Thanks.