1999 GMC Yukon Denali Q&A

1999 GMC Yukon Denali Question: engine replacement leads to no 3rd or 4th gear ?

i just put a new engine in a 1999 gmc yukon denalie it has a rebuilt transmission with less than 500 miles on it , i left the tranny in the truck dureing removeal and installation of the engine i have checked for broken wires with no luck and nothing is unpluged 1st and 2nd work fine but when it shifts to tird it's ike yo put te truck in neutral any suggestions ? -
Answer 1
do u have a ck eng light on -
Comment 1
yes but all the obd2 scan tool pulls is a cam shaft position sencer , no tranny codes at all even after test driveing 3 times to see if issue was resolved -
Comment 2
that will cause serveral issues seek complete diag from your mech -