I highly recommend ARNOTT products.. I purchased two (2) air shocks (complete assembly) for the front of my 4.8is approx 3 years ago - at 48k my original ones FAILED... The ones I ordered from ARNOTT have been lasting me for past 3 years with everyday city pothole driving... GREAT PRODUCT.. superior to the original..

What you said sounds like MOTOR MOUNTS... they are NOTORIUS for going bad, as they are filled with oil, over time the rubber cracks, oil runs out, and the shocks FAIL and dont provide good rebound effect for the engine in the suspesnion dept.. So def def get the ENGINE MOUNTS checked!!

Here is a picture of how they look.. -> http://www.bavauto.com/assets/imglib...3_01_IMG01.jpg

and you can buy here if you want ->
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