This is what I was going to mention, because if the syncros are worn they don't stop the gear the trans is trying to go into from spinning and therefore will make it hard to go into gear.
Whenever there is a hard shifting (like it doesn't want to go into gear when cold) it's always fluid viscosity or syncro ring wear.
Just think about this when involving second.
Second is pretty much always the gear that gets hit hardest and therefore has the most syncro wear.
Fluid viscosity changes can help even if it is syncro wear because thinner fluid gets out from between the syncro ring and gear faster, so it stops the gear faster letting it engage faster.
