Nissan Repair: 1991 Nissan Pathfinder, nissan pathfinder, ring and pinion

Question
We have a 1991 Nissan SE Pathfinder, when you start then engine and step on the gas or put it in drive it has a loud rattling knocking noise.  Can you help?

Answer
Bobby,

Is the noise under the hood?  If so, you could have a broken motor mount.  If the noise is out back it is probably the ring and pinion on the rear end.  If the brake is depressed is the noise louder or not as bad?  Email me back and we'll narrow this down.