2012 5 speed rough shift from 1st to second

This is my first time on here so hopefully I get a response lol I have a 2012 5speed automatic v6 and I’ve been experiencing some rough shifts from 1st to 2nd only when accelerating. (Slow or fast but more common when fast) trucks at 160,000 and I got it at 150,000 not sure if it needs a transmission fluid flush and new filter? Does this seem like a symptom of bad/old fluid, not sure when previous owner changed it all I see is 5qts atf writen under the hood no date. What are other issues that could cause this?

 

I'd start with a transmission oil swap and go from there.

There may be some undocumented damage to the transmission due to operating without a proper amount of trans oil. Very familiar feeling I experienced on a friends '07 tacoma who drove for a day or two with essentially no trans oil.

 

Ok do you recommend a complete flush and new filter, seals and refill? Or is that not necessary?

 

Do the transmission drain and fill. Make sure the transmission is at the right temp first.

https://www.tacomaworld.com/threads/how-to-drain-refill-automatic-transmission.63851/

Make sure to measure what came out and put the same amount back. Add the original Lucas Transmission fix into that amount going back in also. Just make sure that the total amount going in including the Lucas is the same that came out

 

Or you could flush it. But that’s always a gamble with high mileage transmissions

 

I know the transmissions are picky about what type of fluid you put in them is the transmission fix a good idea to put in? Or will it cause problems?

 

https://www.transmissionrepaircostguide.com/lucas-fluid-review/

 

Have someone check the electronics 1st. I've had mice chew insulation off wires that caused funky transmission shifts. With todays transmissions most problems are electrical rather than mechanical. I wouldn't touch the fluid at this point unless I knew it were bad. And if it is bad the transmission is probably toast anyway. Changing the fluid won't only not fix it, but will accelerate it's failure.

In other words find the problem 1st, then fix the problem. Do that before you start down the road of throwing parts at something hoping you find the right one. Unless someone has been towing heavy and allowed the fluid to get too hot it rarely needs replacing. And if you do let it get too hot and don't replace it right away you're screwed anyway.

 

And if you don’t want to listen to general knowledge
Here is a post about Toyota transmission fluid changes from Toyota

https://www.toyotaofmanchesternh.com/when-to-change-transmission-fluid-manchester-nh/

 

Many opinions of trans flushes and many get really heated on the topic.
On my 2009 I had the dealer do a full flush at 115k and after it shifted better and the torque converter lockup was firmer than before.
Now at 160k and I tow so at 165k (50k after last) will have them do again.
At low throttle the shifts will be smooth and at full throttle feel firmer as faster and more torque.
Its a fluid and breaks down and carries worn trans particles in it. I never did a filter as mine has a screen. That's my 2 cents.

 

Careful on a full "flush" at that mileage. Had my 09 "flushed" (BG fluid exchange machine) at the dealer last week with roughly 141K (only 1 drain and fill in its life) miles and lower gears are great, but OD and lockup will slam. Progressively getting worse so only a matter of time before it needs a new trans. Although it was probably already on its way out... Some get lucky, some don't. If it were me I'd just do a couple drain and fills as guidelined by several threads on here.