Sick 4spd

(1) Check your motor mounts and trans mount. Do you have a torque strap? Broken mounts or loose bolts will allow the trans to move and do strange things. (2) Get under the car and check your linkage while some one is moving it from 1st to 2nd. If you don't have the bushings, clips, and washers on the shifter rods they can flop over and rub on the 3-4 rod and cause a slight bind while shifting. (3) A wore out shifter box can do that, too. If those 3 things are ok...my guess would be the syncros. Usually when you start to get a grind going into reverse you need to adjust the clutch.