Out with old in with new

Hello all. I recently sold my 2wd 86 and picked up rt4wd 87. It is brown and in decent shape for its age. It is a 5 speed with the SL gear and has around 140,xxx miles on it. I recently thought it needed a wheel bearing replaced and took it to my mechanic and they said that it was a bearing in the transmission. Ill be on here looking for ideas/ways to repair it. Thanks in advance and I will try to get pictures up in the next few days.