I just bought a 2007 660 4x4. the rear differential was leaking oil bad. After removing axels to replace seals I found what looked like muddy grease. Bearings where wore out and front drive shaft bearing had a 1/2in of slop in it. So I had apart might as well replace every thing. So i installed new transfer case, new gear that attaches to drive shaft, new axels, new break disk and pads. When done I backed up 10 ft put it in forward went 3 ft and then it stop moving. I got out and pushed while in gear and shaft would not turn. Then i rocked it back and forth and shaft started turning again. I tried driving and again I went about 10 ft and it stopped. The front will pull if I put it in 4x4. My question is did I miss any thing during installation? Everything looks to be in place and tight. Or do I have a bad new rear differential.