This is my first post so any help will be greatly appreciated. I have a 2001 discovery SE with about 170,000 miles. When I start it up, I notice a rattling or knocking sound has gotten worst as days passed. It rattles and now when I go to drive off, it has a little vibration. I thought it may have been the transmission so I top off the fluid but no change. While I was under the car, the noise sounds as if it's coming from the front of the transmission. That's about the best I can describe the issue. Does anyone have any ideas?

 

It could be anything.Do you hear it at idle?It may be a cat.A video of the problem would help.

 

Inspect your motor mounts

 

Yeah I Hear it while idling. It does it continuously. I even hear when I give it gas. It speeds up with the engine. At around 30 mph I can't hear it. I'm pretty sure it's not the motor mounts.

 

Use a large screwdriver or a stethoscope on all engine parts to find the noise but if it sounds louder under the truck start there.You will be able to tell when you find it. I still
think maybe the cat.

 

I found that the problem was my water pump and thermostat. The water pump was loose and ready to pop away from the engine. I'll jump on it this weekend. Thanks all!

 

Good to hear!