Weird Shifter problem...

[Chris Richardson]

2008 Sierra 4x4

So starting about a week ago and has got worse on my truck when going from park to reverse drive or any other gear it doesn't work the shift lever on the side of the trans moves like it should but if u shift to drive then back up to reverse (sometime have to do it over and over) it finally goes into gear and drives and shifts perfectly. I thought shift cable was stretched and just replaced it and still does the same thing. I have also noticed once u get it in gear u can then shift to drive reverse or what ever all u want and it works perfectly until it gets put in part again and then the problem starts over any ideas?

[davester]

maybe get codes from the transmission.  you'll need a more advanced code reader to do this.