Hi guys,
My disco has been doing this since I got it over a year ago but its starting to bother me. Whenever I start my truck there is this grinding sound when the idles drop to around 660 rpm. Its been starting to happen when I shift into drive or reverse as well. It is coming from what seems to be the drivers side of the engine bay. It doesnt happen when driving or when it is above the idle rpm. If anyone could help me out that would be great.

 

we can’t help you without some sort of video. It could be many different things.

 

How long does it make noise, if you don't move vehicle? Does it ever go away, like if you've driven ten miles and then idle it again, does noise return? Have you checked trans fluid (must be done with engine running)? Checked power steering fluid? Maybe remove fan belt and see if this changes anything. Does your engine have SAI, could be bad pump, it comes on for a few minutes on start up.

 

I have a feeling it might be transmission related. Ive been starting to notice a rough 1st to 2nd shift the past few days. I will check fluid and change if necessary.

 

Check your transfer case fluid level also, highly overlooked and usually leak. So, while you're under there...give it a look.

 

So I used a stethoscope underneath the truck and the sound seems to be coming from my muffler area or exhaust pipe. Do you think it could be caused by something loose inside the system?

 

Muffler baffles can come loose and rattle.