Grinding Noise

[captluv]

I've heard of some other people having the same issue, but no concrete diagnoses or solutions, so I'll present it again to the group for another analysis.

In the mornings when the car is cold, there is a rhythmic grinding noise coming from the engine bay and it can really only be heard from inside the car and once the engine and transmission are warm, it disappears (although I think I can still feel the vibration slightly through the pedals, but no noise).

I've heard several possible explanations for this including a bad waterpump, but I haven't noticed any overheating and no coolant weeping through the timing cover. So has anyone heard of this before and what can I do to pinpoint the source of the vibration/grinding?

Thanks for any help...

[maxhopper]

It could actually be a number of things.

If an automatic trans; it could be the planetary gear.

It could be bad chain guides.

It could be a bad water pump.

It could be any of the other pulleys.

You have to have someone else who knows what to listen for help you narrow down the location.

[captluv]

This doesn't sound like it bodes well for me. What are the prognoses for bad chain guides or planetary gear? Transmission work doesn't come cheap, just how pressing would it be to get a bad planetary assembly repaired/replaced? Better to just buy new transmission altogether? (YIKES! I might add)

[maxhopper]

The chain guides are more of a hassle to get to than to replace. You'd have to support the engine, remove the motor mount on the passenger side, remove all belts, remove the alternator and water pump pulley, then remove the front cover. Once the front cover is off the chain guides are right there.

If it's the planetary gear in the trans, you'd be better off replacing the whole trans. My planetary has been making noise for a few years. I'm just going to let it go until it doesn't work anymore, and swap in a low-mileage trans from a junkyard.

[captluv]

Another thought on this: I have recently changed my belts and it seemed like the sound got worse after I did. Is there any possibility that that noise could be caused by improper belt tension? If so, what's the best way to check the tension in that sideways engine bay?