My 1993 Cherokee XJ doesnt shift out of first. I replaced the NSS 4 years go and its been sitting outside since then. I would occasionally drive it with my daughter in my lap but not over 15K so I didint notice the gears not shifting. I insured it one day so I could drive it and It was stuck... I looked underneath after getting it going and noticed a rope I had used to tow it was wrapped around the front drive shaft and slighty into the differential. I pulled that off and It shifted out of first but at over 2000rpm. I took it on the highway and it was going OK in first 3 gears but a big thud into 4th and on. Now it wont shift out of first half the time... i was told it could be the speed sensor? Also at high speeds i hear a hum or whirl.