1999 3.4l manual transmission problem

Hey everyone!

So I've been having problems with my transmission, it has a hard time going into gear sometimes. I have to jam in the first lot of the times and sometimes won't going into any gears at all. I've noticed sometimes if I pop the clutch pedal if you times helps a little bit but still first gear is usually pretty rough and clunky. I've already replaced the bushing and see with Marlin crawler parts and I've recently done a oil change with the redline MT 90. I know it could be a lot of things I'm just hoping it's not synchronizers because let's be honest that just sucks ass. My truck has 215k and have the clutch replaced around 150k. The clutch never slips it's just the problem putting it into gear. Has anyone else had this problem or can point me in the right direction before I go to spend $100 at a dealership having them diagnose it. Thank you