4 speed grind

My 97 VN1500 D2 Classic tends to grunt and grind when shifting into 2nd gear. I adopted a way of shifting to avoid this embarrasing noise. Just before disengaging the clutch, I put pressure on the shift lever. It throws the gear right in there. Is this common on the 4 speed Vulcan? My bro in law has a 98 VN1500 with a 5 speed and it shifts like a charm.

I noticed it starts to grind when the engine oil reaches hi-temp. I put good quality oil 1 month ago. No change. I put an additive called Dr. Detroit. No change.

Would appriciate any feedback

Thanks