'06 Nissan Altima makes grinding noise when breaking and loud rattling when in low gear

Hi folks. My '06 Nissan Altima suddenly started making a very loud rattling noise as soon as I put it into drive and start moving at low speeds. The noise does not go away at high speeds. It sounds like I am dragging the entire undercarriage. When breaking it grinds very loudly. All of this is sudden. Only other issue I had recently was that the motor wouldn’t catch when I tried it Saturday, but it finally did after giving it a good amount of fuel. Drove it 300 miles yesterday without a problem. Woke up to a car that sounds an awful lot like a plane. Any ideas? Many thanks!

You start engine. Motor rattle when shifter is in park? Or rattles when u select “drive”?

If it’s grinding when braking, I would have my brakes checked. When was the last time your pads were replaced? Does the rattling go away when the brakes are applied?

To Cavell: rattling only in drive, but park, but should note the automatic gear seems “stuck” when shifting (no longer shifts easily). This started today.
To knfenimore: Brakes replaces last year. Grinding is SO loud when brakes applied hard to tell, but I believe yes, rattling goes away.

You definitely need to get your brakes checked. Please do so ASAP.

The rattling is probably just a rotted heat shield under the car. That can easily be secured by any shop with a worm drive clamp. It could also be a plastic splash shield or wheelwell apron. That too can easily be secured. But you should get it to a shop ASAP in case it’s something more serious.

Get you brakes checked as @the same mountain said. Replace with OEM brake pads.

“…the automatic gear seems “stuck” when shifting (no longer shifts easily).”

Check for a broken motor mount.

you need to get to a mechanic asap, every mile you drive may add money to your bill

+1 to insightful’s post. I’m embarrassed that I didn’t think of it myself.

I will agree that insightful has provided a good possibility for problems with the shift lever, but in an era of electronic controls for the transmission–rather than a mechanical linkage–I think that broken motor mounts and/or transmission mounts are less of a likelihood as a causative factor than on older cars with mechanical shift linkages.

My brother had this exact problem with his '55 Chevy, and it turned out to be broken transmission mounts, but the OP has a car that is far newer than that old Chevy with its mechanical linkages.