Wont shift in to Drive

1997 blazer ls 4x4 auto

While i was driving around pittsburg(very hilly) i down shifted in to 3 to keep the tranny from kicking in and out of OD. It would down shift and up shift back to back i figured it would be the right time to drop it to 3rd, ive done it before no problem. When i did the shifter didnt really click in all the way, the trany was in 3 but the shifter didnt have the positive click it usally does when u put it in a gear but once i made it over the hills and poped it in drive it went right back to OD and ran fine. I got home put it in reverse no problems park no problems. everything is fine. I went to leave i put it directly in to drive and nothing. No movement it just reved up. after playing with it. i can put it in 1,2,3 and R no problem. If i want it in D i have to put it in 3rd then pop it in D to get it to be in D. The trany is a fresh rebuilt, the tranny fluild and level are good and clean. Im assuming it may have to do with the linkage. I poped under the car and w/ a VERY trust worthy freind made him go in to each gear. And when it goes from 3 to D it moves alot more then all the other gears. When it goes from N to D it hardly moves And by It i mean the arm the stick out of the tranny where the coble is connected to. I called the shop and the head guy is out of town till thursday, witch is no big deal, im in school and i dont need the car right now. I wanted to know in the meantime what you guys think it may be, maybe its somthing i can quick fix?

Cable adjustment seems to be in order. You may also want to check the cable at the floor shifter end to make sure it is anchored firmly and not loose.

ok ill see if i got some time to rip the consol out, its not that hard. looking at the tranny, the arm that the cable clips on to is snug and it doesnt look like theres anything visually wrong or out of wack, where the cable gets held at the rear of the tranny is firm and doesnt seem like there is anything visual wrong as well, nothing that looks like it was hit by anything or wear and tear, and it doesnt look like there is any way to adjust it there ither. so i guess unless its the shifter it self or a linkage by the shifter. Since the car drives fine when i do get it in to gear, is there a possiblity there is something internally wrong with the tranny?

Also when im in each gear, the shift just doesnt seem like its "lock" in a gear, It almost feels as if the saftey button on the side is pushed, I can NOT move the gears unless i push it in, but it has, "slop" i guess you could say