3rd gear's a little crunchy, how is it supposed to be? Options

[VavAlephVav]

This is the third 5-speed I've owned in my time and it seems there are a few behaviors common to all of them.
1. it won't let you shift back into 1st gear until you are damn near a complete stop.
2. when you shift down into 3rd gear it gives a little crunch. not a great big noisy grind but just a little.
Maybe at some point I got the Idea that 3rd was made this way intentionally so that you could tell if you were
going into 5th or into 3rd, maybe as to avoid shifting down into 3rd when you thought you were going for 5th.
but I realize that I have no idea if it is really supposed to be like that or if I just made that up.

So how is it supposed to behave? Is it normal to make a little crunch when you shift down into 3rd or does that mean something needs to be adjusted/changed?

btw I just changed the fluid with 80-90w Casterol, and the stuff I drained out was real clean looking. no difference in the way it behaves before or after.

[ILoveMySilly97]

Drain the old oil and pour in the infamous Pennzoil synchromesh. It works wonders.