Hondo
Member
If the chain drive transfer case is still around, I would do a sanity check and see what direction the speedo drive turns on it. Are the physical locations of the speedo outputs on the old and "new" transfer cases the same? Top or bottom, driver or passenger sides? Have you checked to see if the speedo works while backing up? At this point I would considering disconnecting the front of the rear drive shaft. The speedo drive gear is on the rear output shaft, so you could do some checks with it in gear and running. They do make reverse drive adapters if needed.

