COLD START GRINDING SOUND When.

COLD START GRINDING SOUND

When starting my car, there's a horrendous grinding/vibration noise coming from the passenger-side of the engine block. It is most evident in Park and Reverse, though definitely apparent in Drive as well. Goes away after about 5 minutes drive time, and is much worse in the morning when it's cold outside. The "grinding" comes and goes in those first few minutes, often more noticeable when turning the wheel. The grinding almost sounds like "slipping".

As the noise dies down a bit, it comes back for a split second when I go over the speed bumps on our street -- and always on the down side of the bump.

I did notice that the rubber part of the torque rod was cracked and had it replaced. My mechanic suspected that was the problem, replaced it and told me it was fixed, but when I picked it up hours later and started it cold, the noise was still there. To test it, we drove slowly down the alley behind the shop, and while moving, I placed the car in Neutral (no braking) and the sound was still there (coming and going). And of course, after a few minutes, the worst of the sound dissipated.

After the car is warm, I feel like it's still there (though much, much quieter) in Park and Reverse (at a standstill with the brake on), but goes silent in Neutral and Drive (again, with brake).

Unfortunately, by the time the shop can get the car up on the rack, the sound is gone.

So my question is: What can be causing this issue. I guess it makes sense that it could be some kind of mount issue, but why would the sound go away so quickly. Remember, it's completely gone after the car warms up.

Searching the web, I found this video of a Volvo 850 that appears to have a similar sound -- though I will note it is very hard to compare sounds from a YouTube video!

http://www.youtube.com/watch?v=Yw1z8KfNtig

On it, he claims the issue was a faulty bearing in the water pump.

Any thoughts most appreciated!