When i have the truck iding with the jake brake/engine brake swith on the engine makes a louder knocking noise. It immediately quiets down when i turn the swtich off. Im wonderng if this is normal since i just got the truck from a private owner.

 

Yep

 

Really? Thats good then. I was paranoid something was wrong. Whats the noise anyways?

 

Variable Gate turbo motor changing the vane position when you turn it on. Why I do not know, but think that it is spring loaded and when it turned on it move it out slightly maybe for response time(less distance to move when actuated)Maybe someone else has a better explanation. Maybe with the thing off it locked so that it does not move and when you turn it on it unlocks and moves it out slightly so the locking mechanism is unlocked and is ready for the motor to move it when really turned on by the ECM. Have not had to replace one yet in 140k so I have not had the chance to take one apart to see why

 

The EB can be used as a warm up feature for the engine. It will engage the EB at idle and even at high idle.. I use it all the time to get the engine up to temp faster.

The Variable Geometry Turbo doesn't use a spring IIRC. Its all positional servo controlled, ie the servo moves to precise positions based on voltage. The larger versions of the turbo use air actuated cylinders to do the same function.

 

Cool. Thanks. Just making sure its normal.