Timing Chain Kit GMB Water Pump Fit 07-11 Chevrolet GMC Hummer Isuzu 2.9L 3.7L. The timing chain is located in the front of the motor and is attached to a set of gears and pulleys that power multiple mechanical components, including the crankshaft and camshaft. In order for your engine to fire, the timing chain must smoothly rotate around the gears without hesitation. Although the timing chain is made out of metal, it is subject to wear and tear and may break if not replaced as recommended by the factory. Since the timing chain can go bad and will need to be replaced, it is important to be able to recognize the symptoms so you can have it repaired before it fails completely. Signs your timing chain needs to be replaced include: Your vehicle has a rough idle, meaning your engine shakes. Your car backfires. The vehicle seems to be working harder than normal. Your car will not start at all, indicated a complete timing chain failure. Be sure to use our aftermarket replacement timing chain kit when your timing chain is serviced for the best performance.