212 grader transmission question

my grader cat 212 serial 1u-166 has a problem i cant figure out --- i cant find / get it into 1st gear it has a 4spd trans w/ 1st all the way over to the right on the pattern rv and 3rd in the middle and 2nd / 4th on the left of the shift pattern. even if it does not want to "fall into gear" all the other gears you can at least feel a notch or place for the lever to shift into but if you go to th right it all fells smooth no notches grooves anything suggesting there might be a place for first gear. iam sure once i get the operation of the unit down 1st gear would be way to slow and i doubt anyone used it before me but since i have no idea what i am doing out there i should run it in 1st gear so i dont destroy the driveway as fast 🙄 any suggestions on what to check look for have tried engine running not running clutch in clutch out sever rpm ranges hoping to find it but still nothing ----- scott

Along The Right Side Of The Transmission Is An Interlock That Is Also Tied In With The Clutch When You Push The Clutch In The Interlock Shaft Slides Down Into It's Housing Releasing The Interlock.. If The Control Rod Is Bent It May Not Push All The Way Down I Have Seen It Rust And Then The Control Linkage Rod Bend. There Are Four Bolts That Hold The Assembly On To The Side It Pulls Out And There Are 2 Plungers And 2 Springs Make Sure Everything Slides Nicely And Reassemble With New Rubber Boot. The Boot Keeps Out The Water And Crud. If You Remove The Assembly The Machine Should Shift Fine But Sometimes Pop Out Of Gear Oil Is Pumped To It As Well

thanks for the info ill check that out and see if that helps. that rod wouldn't affect the other gears ??? as they all shift fine. like i said before though once i get the hang of the machine i doubt ill need first 😉