@DanyelleW
It could be a click of the propeller shaft much like this fella diagnoses in this video

Give it a listen and let us know what you think or if you already diagnosed the sound and what became of it all.

Is this the sound you're experiencing by any chance shown in the video below? I called this sound in my vid a gear whine but that was my best guess. Do the think the sound is more of a buzzing or a whirring? I don't know what you call the sounds in my vid. A kazoo is an interesting analogy though ...

Follow up question. What is the part number for the middle gasket, the one which sandwiches between the upper and lower housing. I’ve only seen the gaskets for sale which sit between the lower housing and the head of the engine. These are the following part “Volvo Thermostat Housing Gasket - Genuine ...

What are the dimensions of your T30 tools. It’s a tight spot for sure so that torx socket bit must be on the shorter end and it looks it. It looks low profile and has a 1/4 drive I take it. How tall is the bit when its socket end is resting on a table?

I had a bad lower control arm rear bushing go out on me. I'll be pressing out the bushings and replacing them with some good Volvo parts. I just wanted to see if someone can lend a helping hand with some torque spec references for any front end specs they can retrieve.

I have to remove the control ...