2011 Tacoma Absolutely hates 5th gear

So I've had my 2011 tacoma for 5 years now and its been great.V6 trd sport. It has 77,050 miles on it as of this morning, but in the past 6 months about twice or three times a week, the trans WILL NOT shift into 5th unless I put it into 4th manually, then back into drive and it will shift immediately into 5th. Its the automatic trans and this only happens at highway speeds. Its got 35's on stock gears, and it was ok shifting with that for about a year, so i don't think its the big tires with stock gears. Any ideas to whats up is greatly appreciated!

 

I have the same issue on my 2013 on 33's. Switching to 265/75/16's this weekend. Hoping it will no longer be an issue.

 

It certainly seems like the issue. Maybe the colder weather or low fluid level and increased drag exacerbates the symptoms. Regardless, trying OEM tires and checking trans fluid levels would be my first checks too.

 

Deff not going back to oem tires, lol. But i had the trans flushed and refilled in june. Im going to try new gears next.

 

I hear you. In every conversation I have had with Toyota techs, they see no big deal with the small size increase you suggest. Having said that, before I started going down the money pit trail, I would try on OEM tires as a base line test if your friendly mechanic has no other suggestions.