Transmission wont engage!

[cr8zbonneguy]

Hello guys, i recently bought a 2005 gxp wrecked in the front but looks to be superficial.... anywho i bought this bonneville for $300.00 car turns on sounds great but will not move forward or backwards! You can move the shifter in all gears and park, indicator moves but no movement in trans no noise, no nothing. Ive tried to see if its the linkage doesn't seem like it's the issue? only code i get are O2 sensors.... don't think that would cause my issue? Heres a little background on the car the KID I bought it from said when he wrecked it that he replaced the radiator and that some how it overheated and then the transmission didn't work anymore after he changed the radiator and overheated? Doesn't overheat on me engine runs fine ac works and heater. Now im not a professional mechanic but i know my way around GM Vehicles with that said i dont think that would cause this issue? Ive owned 2 cadillacs one 2000 deville and 2006 dts same engine and transmission combo! I like to think these transmissions are built well! Engines on the other hand are pretty awesome but can be a pain. Now Looks like there is transmission fluid in there. Doesn't smell burnt looks normal.... again no movement whats so ever when put in D Or R or 123.... does go in park nd hold in park and moves in N cause when i picked it up was put in N to load on dolly. Any help guys would be awesome. By way i have searched this forum and no luck all 28 pages.

[harofreak00]

Checking fluid level on the 4t80e is kinda tricky.

Start the engine and operate the vehicle for 15 minutes or until the transmission fluid reaches an operating temperature of 82-93°C (180-200°F).
Park the vehicle on a level surface.
With your foot on the brake, move the shift lever through each gear range. Pause for about 3 seconds in each range, ending in Park.
Apply the parking brake and let the engine idle for 3 minutes.
Remove the transmission fluid level indicator, wipe the indicator clean, and reinsert the indicator. Give the indicator a full twist to close.
Wait 3 seconds and remove the indicator.
Read both sides of the indicator. The fluid must be within the hot cross-hatched area using the lowest level reading.

[cr8zbonneguy]

Thanks For the reply...didn't quite check this way but even if it was low i would think it would try to engage or some movement??? I've had a low fluid transmission before...by the way thanks harofreak i had messaged you on Facebook about a front clip.

[CMNTMXR57]

Provided all fluid has been checked and at at sufficient levels, it could be something as simple as the lever having a loose or missing bolt, up to having blocked channels in the valve body or somewhere in the case, spacer plates, etc.