8 3/4 rear end

moparwedden said

OK here is the problem, put in gear, drive shaft turns but will not move car under load. New 727 tranny, rear end just put together ,not by me. Axcels are the right length and housing is too. lift car up and tires will turn, is there something wrong with the third member?

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Does the drive shaft increase speed under the load. If so you have a rearend problem if not there is a problem on the tranny side. Need some more details and conditions here to give much help. Tires on ground or in the air. Just give us all of what you have. Could be some as simple as the yoke isn't going all the way in to the transmission.