The main reason for having the transmission apart was to install a MFactory LSD. Pressed on new bearings, installed in case to check thrust clearance, got that all dialed in i believe. I proceeded to install gear stacks & shift forks, made sure i can engage every gear. 1-5th engage no problem. Reverse i cant seem to get into, however my main issue/question is when i have it in neutral, i went to spin the differential to make sure everything operates smoothly and after about one full spin, it just stops. I then tried to spin it the other way and it does the same exact thing. The diff & gear stacks spin together so i assume they are installed and seated properly. I am not sure if the mainshaft or countershaft is causing this. Maybe this is normal, however it does not make sense. If i were to leave the vehicle in neutral, one can push the car forwards or backwards. I put it into all gears and tried free spinning by hand, same issue. If pictures will help diagnose (Mista bone i know you like pictures), i will post.

 

Got it figured out. when i originally removed the reverse thread bolts that hold the ring gear to diff, six of them came out stripped. So please do not make the same mistake i did and Do not use an air impact gun. Break them loose with first with breaker bar, then you can use air tools to zip them out the rest of the way. I ended up buying 10 bolts used from a fellow i met online that way local to me. I Assumed that b series diff's used the same bolts, so i didnt even bother to ask if they were from a s40 transmission. Turns out that b series bolts are longer then the the d's. About 3mm's roughly, which caused the bolts to stick out just enough to hit first gear. Maybe this will help someone out in the future.