Grinding noise from rear

[Coyoteh]

I'm getting a somewhat loud grinding noise from the rear of the car. The noise lasts for about half a second, and only happens under medium acceleration near the top of 1st gear. It sounds to me like it's coming from the rear.

Transmission? Driveshaft? Differential? The car is an automatic, by the way.

Thanks

[BlackBMWs]

Hey Jamie!

I only have manual transmissions for my 318's. But, just for more info for smarter dudes:

• Is it consistent at each acceleration?
• Only 1st gear?
• Has the fluid ever been checked in the tranny?
• Is it forever fluid, or has a periodic change schedule? I don't know which tranny you have.

I don't think it's the diff based on the base explaination, but when was it last serviced?

Left field guess... 1st gear acceleration, load on rear. Could it be a broken RSM?

[Coyoteh]

Is it consistent at each acceleration?

It is consistent during medium acceleration, doesn't happen during light acceleration. I haven't tested hard acceleration, not sure that I want to. This is all from the 15 minutes driving home though, so it's not a huge sample size of information.

Only 1st gear?

So far it's only been in 1st.

Has the fluid ever been checked in the tranny?

Not entirely sure on this one, I've only had the car for a few months.

Is it forever fluid, or has a periodic change schedule? I don't know which tranny you have.

Again, not sure.

when was it last serviced?

About two months ago, for an oil change and check-up.

Also, for clarification in case needed, the car has 138k miles.

[Bobtail_Bimmer]

Mine ws doing the same and ended up being a worn drive shaft center bearing. I thought it was coming from the dif but it wasnt. Not saying thats what you have but another place to look.