Transmission problem?

Hi everyone! I am not technically a new member, but usually just read forums so haven’t posted. I have a 2005 Tacoma 4.0 A/T 2WD. I have had it since 2006, and bought with 11,000 miles on it. Been having a problem with gears not shifting as should. When accelerating at 10-15 and at speeds of 40-50 the gears will not shift up as should. When I let up on gas pedal then push again, they will shift and seems fine. But yesterday, for first time, at approximately 25mph it shook for about 3-4 seconds. Can anyone tell me what’s causing these two issues? I am not a mechanic or mechanically inclined but want to know what could be causing the problem before taking in as not to get screwed by a shop. I appreciate any info! Thanks

 

Welcome to TacomaWorld
Check transmission fluid level

 

Welcome to TW!

 

Thank you for all the links and for the welcomes!

 

Welcome. Btw when was the last time the AT fluid been changed. If it hasn’t, drain and fill is better for the year and mileage. Don’t do flush

 

Thank you, that is my next thing to try!