2005 Tacoma - hard shift from 3rd-4th gear (automatic)

Hi all! I am looking for help for my beloved Tacoma.
Specs:
220,000 miles
Automatic

Recently we've noticed that occasionally when transmission shifts from 3rd to 4th gear, there seems to be a hesitation. Not always just maybe once every 40 miles. We took to repair shop and there was a leak in the transmission "pan" and the fluid was low and dirty. We had the pan repaired and transmission flushed and replaced with all new fluid.

Fast forward 2 days, transmission did it again.

We took back to repair shop and he claims that all the electrical tested out OK and that all of the test he runs show the problem is "internal in transmission". He's just a small shop so he suggests we take it to someone who handles tranmissions.

Has anyone had this problem? If so, any suggestions or advice?

Thank you so much!
Leigh Ann

 

Likely related to the accumulator valve that modulates the 3/4 shift. Could be worn out and leaking/sticking. That would cause unpredictable shifting. That is internal to the transmission and might be replaceable. I would talk with another transmission shop. With that many miles, it may not be worth the money spent.