Normally it would be one of three things.... ONE- tranny fluid too low TWO- Torque Converter Three-(worst case) bands in the transmission worn or out of adjustment
The linkage that connects the shift lever to the transmission could be out of adjustment or the reverse gear in the transmission itself could be bad. Usually it's the linkage.
Could be a linkage problem..
Yes. Could just be that the linkage is not engaging reverse properly, try disconnecting the linkage at the transmission and manually putting it in reverse, if this works then you just need to adjust the linkage appropriately.
Mis adjusted shift linkage, internal failure
The shift censor could be going bad. There may also be a problem with the transmission linkage which would cause this problem.
could be either transmission shift linkage not engaging reverse ( stops at neutral ) worn joint connectors sometimes cause this. or reverse clutches or gears bad inside transmission.
pretty vague, could be worn linkage in your gear box that pushes the switch.
The linkage could be bad.
Possible shifter or linkage problem? ie: not actually going into reverse. Ummmm, you didn't zoom the tires in reverse and blow the gear did you... Hope that helps.
If you physically can not move the gear shift lever into gear, it could be a problem with the shifter linkage or the transmission. If you can select a gear by moving the the lever which is attached directly to the transmission, it is the linkage. If the lever moves into a gear but the mower doesn't move, it could be a broken belt or a bad transmission.
Check fluid level Could be a bad pump inside the transmission
Your 1996 GMC Sierra truck might not go in reverse because the transmission fluid is empty. You might also have damaged the transmission or the transmission linkage could be broken.