Super D

I'm having a b*tch of a time shifting into 3rd and 4th, but only at high RPM's; low RPM shifting is no problem.

Anyone experience this?

Synchro prob?

Other?

Please share if you had the same problem, and what the solution was.

I'm using a Pro 5.0 shift kit, but if it was the shifter, the problem should exist under load and not so this shouldn't be a factor, right?

Thanks very much.