Trans drain and fill

I visited a reliable transmission shop while I was waiting for my wife’s car to be worked on right around the corner. Had the conversation with them about drain and fills on specifically my truck ‘07 with 143k on it. They said there should be no problem with drain and fills. It’s if I were to do flush that I could stir up problems.

Before I went to the transmission shop I stopped by Toyota to get my oil filter for my truck. I asked them the same question. (I asked the parts guy who I know has more useful knowledge then most of the service guys there because of his previous history with cars and lubricants) he told me pretty much the same thing. Don’t flush, drain and fills should be perfectly fine with no issues.

I have read many posts in here and I was wondering if anyone developed a problem after a drain and fill with 100k+ on their truck.

 

Drain and fill several months ago. ~160k on the clock. No issues (other than it shifting MUCH smoother).

 

I like to hear that

 

Another data point, I did a drain and fill at 175k miles, 10k later with no issues. I used Toyota WS ATF and followed this write up, which has the proper procedure to check fluid level.

 

Hey guys have just a general question and forgive me in advance b/c my truck/mechanical talk is suspect at best

My truck is making (to me) sounds of possibly some strain when trying to shift when i'm driving. I don't know if this has been sounding this way for awhile or if i'm just somehow noticing it more now that the roads are quieter during this pandemic. I have a 2008 TRD Sport Automatic Transmission with 183,000 and some change miles on it and have not had any other problems with the truck since birth. I recently took her in to the Toyota dealership last week for a V6 tuneup with spark plug change and they also performed an induction system cleaning.
Any thoughts ? maybe this is in my head. I don't know all the other maintenance performed and Intervals as i'm sure many will ask me (I know i've been a bad taco dad somewhat), but I've performed all the oil changes on time and i'm sure i've passed on some of those flushes and such that they've recommended to me at the other oil change places (not dealership).
- could this be transmission based? I don't know how to really describe what it sounds like other than it sounds like it's trying to change gears but not really progressing. the RPMs are remaining constant in low so it's not like they are showing high.

would an OBD2 guage connector tell me anything if I got one? was considering a Bluedriver. thanks guys.