2009 Tacoma transmission abrupt shifting issue?

I have a 2009 Tacoma, 4 door LWB 4wd V6 with 131K on it. I bought it with 64K on it and have had no problems at all with it. In the last month I've noticed when slowing down, (coasting) from about 45 mph, it will down shift at about 37 mph+/- and it seems more abrupt than I remember it ever being.
The transmission has always shifted very smooth up or down, especially when downshifting to the point where you almost can't tell it's down shifting but now at about 37 mph you can feel a very noticeable down shift. I had the local Toyota dealer change the transmission fluid and filter hoping I might see an improvement but that didn't help.

I'm pretty certain this abrupt downshifting just started recently and has not been normal in the 67K miles I have put on the truck. The transmission does not leak, slip, make any strange noises or anything that would indicate a problem. If this indicates a known problem I'd like to address it sooner than later.

Has anyone had an issue like this before?

Thanks for any replies.

 

I'd check the driveshaft center support bearing and maybe u-joints. The rubber in that support bearing gets old and lets the driveshaft move a lot more.

 

X2

 

Check trans fluid level.