I have a 75 Bronco with an open-carrier 4.10 est. gears dana 44 front end, that was established by me rotating the front tire once around and counting the respective turns on the driveshaft. I was trying to figure out the rear end make-up by utilizing the same procedure and when I rotated the drivers side tire once around with the passengers tire on the ground it rotated freely but the driveshaft only went around twice, knowing a little about gears in relation to the speed of my vehicle this has me stumped because I was expecting it to turn around at least 4 times???? My brother thinks it may have a Power-Locker that is just free wheeling because of the lack of resistance, any thoughts would be greatly appreciated. I only ask because the Bronco was bought from a kid who knew nothing of the history, the rear end had some salvage yard writing on it (making me believe it is not original), and most importantly I am not ready to tear it apart or tear into some mud to find the answer..... plus I like learning Thanks Mark I do think that the rear gears are in the 4.10 range I just am curious on the carriage.....