It seems that when I go to shift into 4th gear I get a semi crunch sound. I can ease it into 4th gear w/o any crunching. The transmission is a rebuild about 2 years ago and has been driven approx. 1,000 miles since. (purchased from some lady who had it storaged). Any ideas what could be causing this? Could it be a bad syncro?

 

most likely! possibly low gear oil also..... that happened to me

 

Get thee to the nearest autozone and get 3 quarts of pennzoil syncromesh tranny fluid. Go home and change it.
I'll bet my overweight beagle that the problem will be gone.