1997 chevy blazer 4*4 will not go into reverse , drives and shifts sluggish in forward gears . parked overnight went to back up the next morning and vehicle was like neutral in reverse. fluid level is ok .

You may have a bad revers solenoid. Check the fuse and look for any of the fuse to be bad like the transmission fuse. Best thing to do is get the blazer scanned at Auto Zone free of charge for any DTC codes that may be affecting your transmission's performance. Try this, place the ignition to the run position and pull the ECM(BATT) fuse out for 30 seconds and then place it back in. Start the Blazer, it may stall but let it. Just start it again the ECM is just relearning the engine and transmission, let it idle for 1 min and then go for a test drive. This should reset everything in the truck's ECM like the day it was first started and any DTC code will be new and active. Do not add any additives like lucas transmission fluid repair, that will just make it worst. Any additive that may the transmission thicker will make the fluid retention more making the shift solenoid stick causing shift conflicts. Good luck and keep me posted. No revers is ether a bad solenoid, bad PCM signal, or broken sun gear.