Slips out of 1st

[cosgig]

Once under load it doesn’t pop out? Sounds like my car, mine started when I put a new boot on, which is much stiffer than the old ripped up one, now there is pressure on the shifter when not under load and the boot pulls the shifter out of first. Not saying that’s the problem you’re having, but it’s something to check.

 

[matthon]

getting 1-2 and 2-3 to shift was easy, but then R would be inaccessible.

Spitballing here, are the rods correct?
I had one with the wrong reverse rod cause this same issue, and another were the 3/4 rod was wrong.

I can't stress it enough, because it's very easy to check.
Pull the shifter rods and arms set the arms back on the gearshift levers by hand and twist back and forth.

If the arms rotate before the gearshift levers, even a little, it causes problems.

I've had multiple trans were this was the issue, the first one I bought a new shifter first and wasted hundreds.

It's good to use the kiss principle first.

 

[DynaBro]

Arms are all correct. The R arm has a lot of play on the adjuster end but that's not the issue. Otherwise everything is pretty tight. The boot is loose enough that that's not involved. I think it just needs a rebuild.