Hum in 5th gear only

Hey folks,

I know there has been some discussions in the past on the 5th gear hum pulsating drone from 45-65 mph. Is this a normal thing? Truck is a 2018 tundra trd sport with 61k miles. Grandpa driven with regular maintenance etc. I just need to know if I have to spend some money getting this thing diagnosed.

recent work: Toyota dealership replaced tranny fluid and I put new tires on. Wildpeak aT4ws.

no vibrations, just the weird pulse sound.

 

I am currently having the same issue with my 2019 Tundra. Have you figured out what was causing the problem?

 

Welcome from OKC! 45 mph in 5th? Why? These trucks can be limited by downshifting out of D and selecting the appropriate highest gear for the terrain. In the city, I usually roll iaround with it limited to 4th unless expressway cruising around 65+. Never see 6th unless out on the highway pouring on the coal.