Erratic shifting in sport mode-tuning prob or trans prob?

[smittyseng]

2010 SS w 6l80, if you are going 60 or faster and shift from normal to sport mode , about every 10th to 20th time or so it will squawk tires and rev as if you just banged it down into 2nd or 3rd, steady throttle, off throttle . Car has 23,000 miles, still completely stock, bought it 3 weeks ago from original owner. After it does that it hangs there at 4 or 5 thousand rpms for about 3 or 4 seconds then shifts into the gear it actually should be in, other times it goes in smoothly and stays in the gear you are in. About the same frequency, if you take off from a dead stop in sport mode it hangs in 2nd or 3rd gear and wont shift even when you back off gas for a few seconds. I build transmissions for a living but havent had a 6l80 in for work yet, seems like a bad solenoid or sticking shift valve, could be in tps or other sensor I guess making computer confused? Funny thing is it has never acted up in D so I dont see it being a solenoid or it would do it then too. Any suggestions as to what to chase after so I dont waste my time, sure that if mine does it then there are others that have too, thanks, Smitty

[JANNETTYRACING]

Originally Posted by smittyseng

2010 SS w 6l80, if you are going 60 or faster and shift from normal to sport mode , about every 10th to 20th time or so it will squawk tires and rev as if you just banged it down into 2nd or 3rd, steady throttle, off throttle . Car has 23,000 miles, still completely stock, bought it 3 weeks ago from original owner. After it does that it hangs there at 4 or 5 thousand rpms for about 3 or 4 seconds then shifts into the gear it actually should be in, other times it goes in smoothly and stays in the gear you are in. About the same frequency, if you take off from a dead stop in sport mode it hangs in 2nd or 3rd gear and wont shift even when you back off gas for a few seconds. I build transmissions for a living but havent had a 6l80 in for work yet, seems like a bad solenoid or sticking shift valve, could be in tps or other sensor I guess making computer confused? Funny thing is it has never acted up in D so I dont see it being a solenoid or it would do it then too. Any suggestions as to what to chase after so I dont waste my time, sure that if mine does it then there are others that have too, thanks, Smitty

Sport mode adapts to how you drive and will hold a gear much longer anticipating your going to get back in to the throttle.
Normal.
Ted.