2009 Toyota RAV4 pulsing noise

Hey guys I have a question about my baseline 2.5L RAV4.

I have searched around and cannot find much on the issues I’m having.

For a long time when I accelerate between 30-40mph the car makes an odd noise. The noise is pulsing and (womp womp) and will vary in length. If I ease off the gas and hold the mph whereverthey are at sometimes the length of the pulses will be longer. They seem to occur especially going up hills. A lot of what I’ve found suggests it could just be a loose heat shield. However the frequency of the noise seems to have been increasing. In addition even more recently as I was letting the car decelerate from approximately 45 to 30 mph the noise inside the cabin would begin to sound/feel as if he car was going over small rumble strips. It reminded me of the sounds 18 wheelers make when they decelerate. Once it left that band or I accelerated again it would stop. My mechanic seemed to think it was the drive shaft going bad. But did not feel like the pulsating noise was in any way connected to the new issue. He luvricated the drive shaft and the second issue has stopped. However the pulsating continues. I am beginning to suspect my transmission may be going and perhaps is the root of both issues. I would like a second opinion, possibly from a transmission specialist. However I’m afraid if I go in saying I suspect the transmission and dove shaft the garage will see $$$$ and confirm I need it done hoping I’ll have it done there.

I fear the worst as the drive shaft and transmission are expensive repairs. Ther than that the car has had 0 issues and with only 170k miles I’d love to drove it for ears to
Come without getting taken for a repair it doesn’t need, or possibly does. As I do not have a lot of extra income laying around to simply pay for needless repairs ($1000 for the drive shaft, approx $800- $1200 for rebuilt transmission any help is much appreciated.

I have recorded video examples of both the issues and would love any help.

Thank you again
Joseph Kinem

Where are your recordings? post a link if you can. Did the mechanic check the wheel bearings with a stethoscope? They growl when they start to go bad.

Exhaust system needs a closer look. Heat shields, or a small leak - maybe at a gasket - or a double-walled pipe whose inner layer and outer layer are resonating against each other at certain RPMs.