Flat spot on crankshaft
By L. Gebhardt on
2007 GMC Sierra 1500 SLT 4dr Extended Cab 4WD 6.5 ft. SB (5.3L 8cyl 4A)
Gmc decided to fix enginne instead of replacing truck, it had about 2000 miles on it when problem first appeared. It sounded like a vibration coming from exhaughst system, mechanics knew what problem was as soon as they heard it. Flat spot on crankcase. Rebuilt lower end, and gave me a 6 year 90000 mile warranty. BIG DEAL.
BETTER CUSTOMER RELATIONS FROM GMC. The Feild rep. would not even talk to personally.