I own a 2009 GMC Sierra 1500 4WD Crew Cab SLE with the 5.3 Flex Fuel and a 6-speed Auto. Twice this week I have experienced the transmission slip at takeoff from a stop when I was waiting to turn right. The truck has 99,500 miles on it. I had the transmission serviced with OEM fluid and filter at about 40k miles and then again at approximately 90k to make sure I could avoid problems due to lack of maintenance.

On these two occasions I have pressed the accelerator to proceed around the corner and the engine revs up with no movement for a second or two and then kicks into gear and takes off almost as if someone hit me from behind. In both cases, it has been from a cold start situation and happened within 3 blocks of leaving to go wherever I was headed.

Any ideas??

 

"I own a 2009 GMC Sierra 1500 4WD Crew Cab SLE with the 5.3 Flex Fuel and a 6-speed Auto. Twice this week I have experienced the transmission slip at takeoff from a stop when I was waiting to turn right. The truck has 99,500 miles on it. I had the transmission serviced with OEM fluid and filter at about 40k miles and then again at approximately 90k to make sure I could avoid problems due to lack of maintenance.

On these two occasions I have pressed the accelerator to proceed around the corner and the engine revs up with no movement for a second or two and then kicks into gear and takes off almost as if someone hit me from behind. In both cases, it has been from a cold start situation and happened within 3 blocks of leaving to go wherever I was headed.

Any ideas?"

I am about to go look at this very truck with this very issue and I'm wondering if you ever had any sort of resolution to this issue. It would be fantastic to know if I should avoid the truck or if it's just something minor.

 

That person hasn't been here in 5 years. I doubt they're coming back.
I recommend AGAINST getting trucks with Flex Fuel and especially AFM.