Cat -12 first gear slips out :(

bought a Cat 12 road grader (8T1812😎, it slips out of first gear...it does whether under a load or not..all the other gears seem to be fine. Guess it makes sense that first gear is worn out eh...since that is the
gear that gets used the most...any adjustments that will fix this....guess I could just live with it...us a bungy cord to hold it back etc, or my leg. I am a farmer just using it to move dirt on terraces and
waterways...thanks

Probably a worn detent or broken detent spring. Also a possibility of a worn out detent notch on the shifter shaft or worn shifter fork which would require replacement.

thanks for the info

I am not familiar with Cat graders but on the D7 dozers there is a transmission inter-lock mechanism. If the D7 jumps out of gear the detent has become rounded on the end and will not stay in the groove. To fix this, all one has to do is replace it with one that is not worn as bad from another gear. On a D7 fifth gear is never used and fourth seldom used and so one can switch these.

I'd check and see if they use similar system. Also I'd check if it has an inter-mechanism that all linkage is in good working shape (no play).