1985 Chevy c6000 ramp truck with 454 and 465 transmission reverse and 1st gear ?

[stenny]

I have a 1985 Chevy c6000 ramp truck and it has a 454 and a sm 465 or ch465  they are the same 4 speed tranny so first gear (granny) I have to let off the clutch for it to go into gear that he only issue with first gear I wanted to know why that is that i have to let off the clutch a little bit? Also reverse pops out of gear it use to just pop out after like 10mph or so now It pops out after like 2 mph  and if you try to hold it it grinds what would cause these issues?

[Engineer]

Your granny gear is not synchronized so that is normal to get the teeth on the sliding collar to mesh with the teeth on the gear.

If your tranny is jumping out of any gear it is due either to a bad bearing, or a broken shifter poppet spring, you need to get that fixed.

[stenny]

What is the poppet? Is that the half circle  that clicks onto the gear selector?

[stenny]

Ok I looked up what the poppet is and they aren't much money which is good! How do you replace  the shift for and poppet? Do I need to pull apart the whole tranny or can I replace it from top cover or pto cover?