Cat 950F series 2 wont engage forward nor backward ,just sitting comfortably

This machine was bought sitting idle for about a year,but the engine is excellent and it was loaded onto the low bed and also driven for half a kilometre to sand dump it should work in. Only that 2nd and 3rd gears weren't engaging. The operator tried to load the bucket and it crippled right there.
8TK01724
All 6 solenoid have been changed before I got here.
Any suggestions?