Ever since I purchased this truck I have dealt with a transmission that constantly up and down shifts especially at slow speeds. It's as if the computer can't decide what gear the tranny should be in so it keeps switching back and forth between gears. The result is hesitation then clanking as the car accelerates or reduces speed. I have been back to the dealership on multiple occassions and as expected they can't replicate the problem???Ironically anyone I let drive the truck always comes back and says what's up with your transmission. I can't believe I was the only "lucky" guy that purchased a lemon. I wish GMC would at least acknowledge there is an issue!!!!!!
My 2014 GMC Sierra has never good mileage. Yes--it's 4 wd and the 5200 motor but the door sticker claimed it would get much better. Well , I have 17000 miles on the truck now and updating my review. The gas mileage is still very poor with about 15-17 highway and 10-11 around town. The thing I hate worst is the seats for they are way too low with no adjustment to go up. Also, hate the location of the window crank handles for they are too low and hard to reach. Yea--I know--crank windows but this is a work truck but has some great options like 4x4, 5200 motor, ac. great radio and nice chrome wheels. Over all a good truck for the money but come on GMC--be fair on the window sticker on the gas mileage!
Strange to read all the horror stories about vibration, clunks, trans slipping. I have a 2014 Sierra V6 WT with the only options of a locking rear differential and a hitch. I crank my windows. Have about 2000 miles on it now. It is quiet, shifts smoothly, rides firm but it is a truck. It is quite powerful if you lay into it, most of the time I don't and it gets 18-19 city. Not sure about hwy yet but indications are it will get the advertised 24 hwy. No rattles or strange noises, actually it is very quiet. I wish it had a better exhaust note. You have to turn down the radio and concentrate to feel it go from V6 to V4 and back. The reg cab lighting could be better.
bought new at the springfield, vt. gmc dealership. am very happy with it. initially, I was getting a rattling noise in the muffler/driveshaft area. gmc dealer found it was a loose baffle in the muffler. after exhaust system replacement, the sound is gone and has not returned. I get good mileage. has better options than my last new truck(Silverado). Headlights were insufficient at night when new. Gmc had a service bulletin on this issue. They replaced the bulbs(n/c) . Have been fine since. Had a rhino liner sprayed in. Great investment. Recommend keeping tailgate locked at all times. Periodic rash of theft in the area. Very easy to unhinge and disappear. I currently have 10k for mileage. Although i bought the truck in Vermont..i have a local GMC dealer take care of inspections,oil changes,etc. would i buy another GMC ? Absolutely!! Tried to select the year (2014) but drop down menu will not allow.