sthom2255

I just bought a 2014 sierra 1500 4.3/v6 reg cab/reg bed. has less than 500 miles on it and .... I am getting the exact same sound!! I,too, took the mechanic with me to duplicate the noise. it sounds just like a defective u joint!! on acceleration and deceleration. also... when coasting down a hill I get the repeating knocking noise. they did not tell me it is normall, but, rather kept the truck for 2 days until the gmc tech rep showed up. it has been identified as a faulty baffle in the muffler/exhaust system. a new muffler /exhaust system is on order and being installed next week. the tech rep. told us there is a bulletin out on this issue for 2014 sierra's. after I get the new muffler installed..... will let you know the outcome. >>>although the gmc technical representative identified the noise as a muffler/exhaust issue.... I still think it's connected to the u joint/drive shaft area. the mechanic told me they had some 2014 sierra's sl's that needed to have the driveshaft/u joints replaced and noise went away.

I just bought a 2014 sierra 1500 4.3/v6 reg cab/reg bed. has less than 500 miles on it and .... I am getting the exact same sound!! I,too, took the mechanic with me to duplicate the noise. it sounds just like a defective u joint!! on acceleration and deceleration. also... when coasting down a hill I get the repeating knocking noise. they did not tell me it is normall, but, rather kept the truck for 2 days until the gmc tech rep showed up. it has been identified as a faulty baffle in the muffler/exhaust system. a new muffler /exhaust system is on order and being installed next week. the tech rep. told us there is a bulletin out on this issue for 2014 sierra's. after I get the new muffler installed..... will let you know the outcome. >>>although the gmc technical representative identified the noise as a muffler/exhaust issue.... I still think it's connected to the u joint/drive shaft area. the mechanic told me they had some 2014 sierra's sl's that needed to have the driveshaft/u joints replaced and noise went away.