2000 gmc sierra 1500 transmission issue

[Tim duncan]

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.

 

[newdude]

On 10/20/2024 at 10:13 PM, Tim duncan said:

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.

 

 

 

Any codes?  You've probably got something unplugged or broken inside the transmission.