2015 Chevy Tahoe LTZ

[CLAIRE10]

I bought this car from 1 owner everything as transmission flush,oil change etc.. Deleted the 4cyl. Every time I am going down hill or flat road the trans slips 2nd and 3rd if I drive real slow till I get past and hit 4th it doesn't slip or when going up a hill its perfect. Any body ever had this before or what it could be???

 

[Big Mama]

Where are you seeing what gear it’s in or skipping? If you press the gas going down hill dies anything happen other than the rpm’s going up?