Engine

• Some 2005 TrailBlazers may experience failure of the water pump. This component is responsible for pushing coolant through the vehicle's engine cooling system.
  
  

Driveline

• Another common problem of the 2005 TrailBlazer is the failure of the lower pinion seal. As one of the components of the SUV's powertrain, this part plays a role in how well the vehicle moves.
  
  

Cost of Repair

• As of January 2011, repairing the water pump can cost about $310. The front pinion seal costs much less, at around $50.