I have a 2000 gmc sierra 1500 4x4 the rear end exploded so I replaced it now when I put the truck into drive it goes to 3rd but I can manually put it in 1st 2nd and 3rd then to drive it shifts through all gear after I’m rolling but when it wants to go to 1st when I slow it goes to 3rd again.
So I have a 2000 gmc sierra 1500 the rear end exploded I replaced it now when I put it in drive it goes to 3rd. I shift it manually it drives fine. I’m lost I’ve tried unhooking the battery for a few hours and got nothing. I got it to go to 1st in drive for a split second but then back to 3rd. Any ideas