OK, I have 2010 with 4.6 3v, 3.55 L/S with 7k something miles.

Not all the time but every so often I have this problem. I come up to a stop sign in our little towns that has a slight up hill incline and take off without making a complete stop and I get a hard slam and clunck. It feels like what would happen if you did the old neutral drops.

Almost like the tranny/torque converter and drive shaft are not engaged when you push the gas and then all of a sudden lock up and you get the drive shaft type slam.

Only once I was sitting at a stop sign going uphill waiting to cross and I let my foot off the brake and the tranny would not hold the truck as I was rolling backwards as if it were in neutral.

I have heard that the 6speed kinda coast when decelerating and not actually
in a gear as we know it. Don,t know but was wondering if anyone that is a mechanic on these could tell me if there may be something a bit off or is it the nature of the beast.

Thanks.

 

Take it to the dealer, that's what warranties are for. It may just need a TSB reflash.

 

I was told the tranny holds in the highest gear as long as possible while decelerating. Depending on temp and fluid vicosity you may experience a nudge after coming to a stop. Told that's normal. Also what you described with the rolling stop I was told was normal since it's holding in a higher gear, then when you add power it downshifts.

 

Had similar issues on an incline...rolling to an almost full stop from a freeway offramp or driving behind slow drivers up hill. Latest TCM software fixed it.