'14 SILVERADO PURCHASED NEW... I NOTICED THE RIGHT FRONT VIBRATION AT 6400 MI ON THIS DATE ONLY BECAUSE IT WAS THE FIRST MAJOR HIGHWAY TRIP FOR THIS UNIT. 62/74/80 WERE WHERE THE PROBLEM EXHIBITED ITSELF THE STRONGEST. DEALER STATED WARRANTY FOR 2 TIRES, REBALANCED, ROTATED. FUNNY HOW THE PROBLEM STAYED AT RIGHT FRONT.

ON A SUBSEQUENT VISIT FOR RECALLS ON THIS UNIT, I GOT A '16 SILVERADO LOANER W/ 1625 MI. IT DID THE SAME THING IN THE SAME POSITION, BUT AT DIFFERENT SPEEDS. FUNNY, EH?

MY ESTIMATION IS: IMPROPER ASSEMBLY AT POINT OF BUILD, DUE TO UNBALANCED RIGHT SIDE DRIVEAXLES (K SERIES 4X4 ONLY), AFFECTING RIGHT FRONT WHEEL; DRIVELINE CAUSING A SUSPENSION VIBRATION IN EVERY K SERIES 4X4 UNIT PRODUCED TO DATE.

THEY GAVE ME A SURVEY, AND I LET THEM HAVE IT FOR THE WAY THEY HANDLED THE SITUATION, INCLUDING A SUGGESTION TO HAVE THEM CONTACT GM OF NORTH AMERICA... I'M FAIRLY CERTAIN I'M ON THEIR SH*T LIST NOW.

This problem is related to the computer modules controlling the engine, 6 speed transmission, and active fuel management. It took approximately 2000 miles for it develop and it has been getting steadily worse, I currently have 21,000 miles.

The issue is that the engine stays in 4 cylinder mode too long, with a slight load, thus causing vibration in the drive train due to the improper rpm and gear ratios. GM has been made aware of this issue and claims that is a normal by product of active fuel management on a V6 engine. I have owned GM trucks with V8 engines and active fuel management and it doesn't have this problem.

Dealerships have tried the following fixes: Installed body and exhaust mounts per technical service bulletin Run picoscope on vehicle wiped the memory of the modules and reloaded the programs swapped drive shafts.

None of which work. Vibration can happen at any speed when in active fuel management and engine is under a slight load increase, such as an incline, or slight acceleration. Vibration is loud and can be felt in passenger cabin. If there isn't an increased load, the vehicle operates smoothly in V4 mode.

Using the trailering option, which increases RPMs significantly reduces if not eliminates this problem. One dealer suggested purchasing a module to keep the vehicle in V6, this would reduce fuel efficiency by 7 percent. Using trailing mode would also reduce efficiency. The promised fuel economy was the driving reason I purchased a V6 and these fixes eliminate that efficiency.