The upper motor mount connects the block to the driver’s side of the engine bay. This mount is generally the most common mount you will be removing when something breaks on your DSM so get familiar with it. Its held in place by one 17mm bolt that goes through the center and threads into a welded nut on the chassis. Make sure you inspect the inner fender well on the driver’s side for any signs of rust on this nut. If you don’t have splash guards, there’s a good possibility that this nut will be effected and could cause issues when removing or installing the motor mount. The mount is connected to the engine via 2 14mm bolts that thread down into the tensioner pulley mounting bracket which is bolted to the block.
A worn motor mount can cause excessive vibration and jerking when shifting or getting on the throttle.
There are several aftermarket options for motor mounts. You can get solid mounts or prothane inserts depending on your goals. Aftermarket mounts will help eliminate movement of the powertrain, allowing more power to go directly to the wheels. These do not however absorb vibrations as much as stock mounts which can lead to bolts loosening up, so make sure everything is good-n-tite when working on your car.