Okay, so i just recently replaced the engine myself on my 1998 Oldsmobile Bravada AWD. The truck was running beautifly before i replaced the engine but i decieded to change the engine because i was getting an engine tick that was unbearable. Anyways, that being said, now the trans wont start off in first gear and wont shift into od. Could there have been a cable that i disconceted or failed to reconnect when i put the engine in. All the wires seem to be fine. I know that the most common problem for the trans doing this is the shift solenoids. Is there any way i could have broken them even if i havent removed the pan? I always figure things out on my own but i just cant figure it out. Thanks in advance for any insight, it's appretiated.

oh, and i also get these codes(incase it makes a difference)
P1345
p0758
p0753

 

Here are the DTC listings for the three codes your PCM is reporting:
P0753 - Shift Solenoid A Electrical
P0758 - Shift Solenoid B Electrical
P1345 - Crankshaft Position [CKP] Camshaft Position [CMP] Correlation

From the sounds of it, your trans is in limp-in mode which is 3rd gear only when selecting any forward gear. Check the wiring diagrams in the links above to see what is consistent between them. For instance, the CLSTR fuse is common between P0753 & P0758.

It sure sounds like you forgot to connect something and/or connected something incorrectly.

 

Your positive you connected the tranny shift cable correctly? Park is park, 1st is 1st gear, etc.

 

So it endend up being that the plug (on the transmission) broke. I must have broken from tugging on the wireing somehow. Anyways now I have to open up the trans and replace that wireing. Thanks for the help guys!
$50 from advaceautoparts with a sensor.