[DSPTurtle]

Mobil 1 75/90 works well in both my boxes. But I did rebuild both when they first came into the family.
Shift into 2nd and then reverse and you'll have no grinding.
Slow up shifts are reality. Replacing synchros will make it a little better but under no circumstances will you ever be able to speed shift these boxes. The synchro design won't allow for it. It's not hard to do, but the synchro parts are dang expensive.