Adjusting the timing on a gmc sierra with a distributed ignition requires special tools and a working knowledge of engine mechanics. a gmc sierra model. Changing the u-joints in your gmc sierra is a good project for the do-it-yourselfer or home mechanic. the u-joints are located at each end of the drive. If your gmc sierra is running hot, whether it is over-heating or just running at a higher temperature, then it might be time to replace your thermostat. a. You may also like. how to make parking brake adjustments in a gmc sierra. make a parking brake adjustment to your gmc sierra when the truck starts to roll. You may also like. how to change the thermostat in a chevy silverado. if you notice your chevy silverado running hot or the heater not blowing warm air.