1973 big change was to the larger 5-297 u-joint. It still came with ball joints, 2 3/4" axle tubes with ½" thick walls and the Panhard bar was attached with a separate bracket. The axle stayed this way thru 1975 on all F100's & F150's. The 1973 model year also saw the release of the 3.73 and 3.50 gear set in June.
In 1976 the axles coil mounting cast brackets were slightly changed. The front passenger's side was made with the Panhard bar attachment cast in to it. Additionally 1976 was the first year Ford offered disk brakes as a standard option, although several late 75's have been rumored to have disks. This axle stayed the same for 1977 for the F100 and F150. The 1976-year also saw the release of the 3.00 gear set in December.
In 1977.5 Ford's new F250 axle now started to appear. Previously, the F250 ran a standard rotation closed knuckle axle (see reference pictures below.) This axle for the F250 44RS is slightly different than the F100 & F150 offered in 1977. The F250 is a little wider than the F100 & F150, for the wider 8 wheel bolt hub. The F250 also has 3" wide axle tubes with ½" thick tube walls, and the axle has many different small changes from the F100 & F150 to include larger brakes. This axle stayed this way until it changed to the Twin Traction Beam (TTB) IFS system of the 1980 model year.
