2008 GXP with 53000. Earlier this year an odd noise, rattle, started coming from the front of my car. I did some low level testing within the car to try and determine what was making the sound. Here are some details on that:

• Starts around 35-40 mph, presumably when going it to 3rd.
• Stops when coming to a stop at almost precisely 15mph, presumably shift to 1st.
• While cruising shifting into neutral it stops.
• While using TapShift seems to stop.
• While cruising, bliping the throttle stops it for a second and then returns.

Now I originally though this was a tranny issue because of it going away while in neutral and stopping at exactly 15mph at every stop. As well as general tranny issue with the LS4 and the 4T65E-HD. However the tranny is still responsive, meaning it hasn't changed since I first got the car.

After digging through this site I came across several threads that mentioned a similar sound that ended up being the timing chain and it's relation to AFM. Here is a recording of the noise I did several months ago.

http://www.youtube.com/watch?v=B1-b-avFAAY

For those of you that have or had a confirmed timing chain issue is the noise in the video what you were hearing?


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