weird transmission problem

i've been having a prolonged issue with my transmission. It seems to thunk into gear especially when it's colder out. Also only when I come to a hard abrupt stop it will stick in gear when I try to accelerate. I took it to the transmission shop and they scanned it and it came back with a pressure code. What I thought was weird was he asked me to keep driving the truck to make it worse so they could better diagnose the problem. Even weirder after five months it still hasn't gotten much worse. I'm thinking about trading it in to get a new truck but a friend of mine said that I could get it scanned more accurately at a dealer although I can't find any evidence on the internet supporting this. I just want to exhaust all possibilities before I traded in but I would like to not spend anymore money on it if I'm getting rid of it.

 

@gearcruncher

You're busy today.

 

Thanks St Andrew

From the OP,s explanation, there are a couple things that could be looked at but I would never let the dealer ( Toyota ) touch the transmission unless he still has warranty . If he has high mileage http://www.sonnax.com/parts/1778

and here http://www.pdf-archive.com/2012/01/06/tsb-0373-09/tsb-0373-09.pdf

and last but not least .....here http://bluegrasstoday.com/wp-content/uploads/2012/07/a750e_shudder.pdf

Here is a complete write up for the transmission in your truck https://www.tacomaworld.com/threads...th-pics-for-second-gen-4-liter-trucks.289913/

Read through this information and get back to me . Have you kept up with services ?