I have a 2001 Yukon that the transfer case went out. I purchased a used one from a junk yard. The unit I purchased has a different transfer case Encoder motor one has two wire harnesses and the other has one. I tried to switch the units but one encoder has a cog type connection to the transmission the other has an oval connector to the transmission? Is there anyway to switch this? Did I buy the wrong transfer case? They were supposed to be compatible. they both have the same numbers on the transfercase steel tag. What should I do to correct this issue? Thanks for your assistance.