The transmission in my 1980 cadillac deville wont shift into gear. It will go into park but thats it.IS THERE ANY GOOD POSSIBLE CAUSES THAT I SHOULD CHECK BEFORE REPLACING THE TRANSMISSION when i may only need to replace a part?

its very possible ,that's where tranny gets info to shift all your main gear shifting should be done by 35 mph and after 55 is overdrive the other is if you take it for a drive and manualy shift it out from lowest gear to highest and see how it functions, so you can feel the shifting advance then try it again just in drive only and see if you can feel the gears shift out , have you serviced tranny ? is it a high millage car it is 23 years old ,

No adjustment however check your linkage /shift cable. Somethings off track

The parking brake may not release automatically due to a failed vacuum switch or actuator. Our technicians tell us that if vacuum is supplied to the actuator when the transmission is in gear, the vacuum switch is functioning and replacing the actuator should correct this concern.

Yes ,you need to replace only ,after checking vacuum line that runs to it and make sure it's working correct

The governor likely failed. Not a difficult part to find or replace.

If the fluid level is ok then you need the transmission repaired/rebuilt.

Still sounds like the linkage at the transmission. Take another close look while someone is working the gear shift lever.

The first thing to check is the linkage. Sometimes the linkage will slip, Block the wheels on the car (both front and rear) to prevent rolling. Locate the shift linkage on your transmission, and loosen the nut. You should be able to move the shift lever through all the gears, including "P" and "R". Place the transmission shift lever in "Park" (on the transmission) then move the shift lever (inside the car) in the "P" position and tighten the nut (not a bad idea to use a new locking nut here) You should now be able to shift through all gears. If this does not work, you have a more serious problem that may include a worn or broken belt or broken parking pawl inside the transmission.

replace park neutral switch located beside the shift cable

well 1st check your fluid level and contamination and transmission seletor switch on your transmission otherwise your valve body not delivering fluid pressure to apply clutches to get ingear