5 replies to this topic

[Straight6]

I have an 83 Bronco w/3.00 ratio gears, 9 in rear can anyone tell me how many splines it has. Also, is the front diff (D44) reverse direction.

[Seabronc]

Per Dynatrac, most Ford 9" rear ends came with 28 spline axles and without special modification can only accept up to a 31 spline axle shaft. Yes, the 44 front differential is a reverse cut. Reverse cut doesn't mean that it turns backward, but it actually has to do with the spiral direction cut into the ring gear. The effect of reverse cutting is to strengthen the operation of the gear by making it push on the stronger side of the gear when moving forward.

[Justshootme84]

Most Ford 9" rearends in 70-83 model trucks are going to have a 31-spline axle shaft. Best way to tell is to pull one and count. The front D44 TTB is reverse rotation.

[Seabronc]

I beg to differ with Justshootme84. Per Dynatrac, the Dana 44 is not a reverse rotation differential axle setup. It is a reverse cut, and does not turn backwards or in reverse. In a reverse cut axle the spiral on the ring gear is opposite from the standard cut ring gear. That allows it to push on the strongest side of the ring gear when moving the vehicle forward and gives it more strength. In a reverse rotation setup the it pushes on the weak side of the teeth to move the vehicle forward. Ford has used the reverse cut since 1977. The designe also allows for better driveline angles for the shorter front shaft. This wasn't picked up by a lot of other manufacturers untill the late 80's.

[Justshootme84]

Thanks for clearing that up. I always thought it was reverse rotation on the front TTB Dana44 axle. THe site I use for reference for the Ford 9" is down at this time (hiqties.hypermart.net/9inch.html)

[Seabronc]

Looks like they didn't pay their bill Justshootme84. Yah, the reverse rotation was used by everyone untill the Dana 44. It was nothing more than a rear differential turned around and mounted up front with the necessary steering parts.