Humming & Slight Vibrations Between 40 & 60 mph

Okay here’s my first post, need some help.

My 2004 Toyota Tundra 2wd has developed a repetitive humming noise / groaning sound. Along with it comes slight vibrations in the floor. This sound occurs only at higher speeds between 40 & 60 mph. It sounds like it comes from eight under the front seats, but I had taken it to a shop & they put microphones and heard it on the third member.

The sound is more noticeable with slight throttle at those speeds. The shop spent a lot of time with my truck, the noticed my centering yoke on the driveshaft was cracked, and had a full service done to the drive shaft. The rear passenger side axle shaft was bent, this was replaced. They checked tires and they look good. I swapped out the third member with a used one and same noise is present.

Th shop basically gave up and said they cannot find the sound, transmission shop said transmission is not causing the sound. I am pretty lost and don’t know what else to check.
The truck was rear ended about 8 months ago and the sound started happening 4 months ago.
Any one else with the same of similar experience who has any input would be greatly appreciated! Thank you!