In 1980 the Bronco went from a straight Dana 44 front axle to what Ford calls the Twin Traction Beam (TTB) front suspension. The TTB system is Fords version of an independent front suspension, and was used on the Ford Bronco from 1980-1996. Mechanically, the TTB axle is similar to a straight axle, but instead of a solid axle tube, the differential and steering knuckles are attached to beams. The inboard ends of the beams are attached to a frame-mounted crossmember by a bushing, while the outboard ends support the steering knuckles and are attached to the frame through the springs and radius arms.
Dana 44 Specifications:
|Ring Gear Diameter||8.5-inches|
|Carrier Breaks||3.73 Higher / 3.92 Lower|
|Ring Gear Bolts||(10) 3/8″ x 24RH|
|Pinion Shaft Diameter / Splines||1.376 inch / 26|
|Inner Axle Shaft Diameter / Splines||1.31 inch / 30|
|Outer Axle Shaft Diameter / Splines||1.21 inch / 19|
|Inner Axle Shaft Minimum Diameter||1.10 inch (necked)|
|Outer Axle Shaft Minimum Diameter||1.10 inch|
|U-Joints (Dana 44)||5-297x (replaced by 5-760)|
|Maximum Tire Diameter||35-inches|
|Pinion Bearing Preload||14-19 in lbs (new) 6-9 in lbs (used)|
|Ring Gear Torque||55 lbs-ft|
|Carrier Bearing Cap Torque||60 lbs-ft|
|Pinion Nut Torque||200-220 lbs-ft|
Dana 44 TTB Locking Hubs:
Most people are familiar with the locking hubs on Dana 44 axles. The Dana 44 TTB uses the same locking hubs, except for some 1987-1988 models.
For some reason in 1987-1988, Ford used a one piece flange style manual locking hub similar to the ones found on the Ford Ranger & Explorer.
Dana 44 TTB Axle Shafts:
- 1980-1996 Outers (stub shaft at spindle) are all the same unless it’s a 1987-1988 with flange style hubs (9.81 inches)
- 1977-1988 Outers (stub shaft at spindle) is not the same as the above listed 1980-1996 shafts
- 1980-1996 Driver side inner shafts are all the same (15.77 inches)
- 1980-1982 Passenger side axle shafts (intermediate) are different to accommodate bolt on inner shaft
- 1983-1996 Passenger side axle shafts (intermediate) are all the same (24.77 inches)
- 1980-1983 slip yokes are 5.50 inches long
- 1984-1996 slip yokes are 5.062 inches long
Dana 44 TTB Third Member Housings:
Here’s a setup you don’t see that often. It seems that the 1980-1983 Dana 44 TTB and Dana 50 TTB trucks that were equipped with a front limited slip differential also came with a unique housing that held the passenger side axle shaft in externally with (3) bolts. In the photo below, you can see the typical housing on the left that the passenger side axle shaft slides in to, and then the shaft is retained internally with a c-clip. You’ll notice that the housing on the right has a much larger opening to allow for a bearing, and the whole assembly is retained by (3) bolts.
The photo below shows the difference between the passenger side axle shaft that is held in with a c-clip, and the one that is bolted in.
Why would you want this setup? Because you don’t have to worry about a broken c-clip, and the shaft sliding out of the housing when the suspension flexes off-road. Some people put a spring in the passenger side slip yoke to keep pressure on the shaft so it stays in place. This is permanent fix to that problem if you can find the housing with the bolt in shaft still in place.
This is what you would likely see if you were to crawl under one of these trucks and look:
Here’s the Spicer part numbers for the bolt in parts if anyone is interested:
- Seal 35938
- Bearing Assembly 566075
- Retaining ring 36121
- Seal for the other side of the diff is 40710
Parts for the C-clip version are:
- Bearing 566121
- Seal 40773
Ring Gear Gear Carriers:
Dana 44s are reverse rotation hi-pinion. Most are a 3.50 gear from the factory. A new carrier is needed for gears lower (numerically higher) than 3.92
There are (3) styles of carriers:
- Type 1: 1980-1982 gear carriers used a bolt on axle retainer, used different bearings and seals than 1982-1996 (Types 2 & 3)
- Type 2: 1982-1992 gear carriers used a c-clip to retain the axle, used different bearings and seals than 1980-1982 or 1993-1996 (Types 1 & 3)
- Type 3: 1993-1996 gear carriers used a c-clip to retain the axle, used different bearings and seals than 1980-1992 (Types 1 & 2)
Dana 44 Spindles:
Not all Dana 44 TTB spindles are the same.
- 1980-1992 – These spindles are basically the same, but the keyway slot is cut past the threads on one of them. These spindles have a 6-bolt pattern.
- 1987-1988 – These spindles ares completely different and shorter to work with the flange style locking hubs
- 1993-1996 – These spindles use a different size inner bearing, and the ABS versions of these spindles have holes cut in to the flange for the sensors. These spindles have a 5-bolt pattern
If for some reason you need to replace a spindle, you need to be sure that your ordering one that matches the one your replacing.
See the photo below for reference.
Dana 44 TTB Steering Knuckles:
- 1980-1985 Knuckles have bolt on calipers and 6 bolts holding the spindle to knuckle. (strongest?)
- 1993 Knuckles have tension pin style calipers and 5 bolts holding the spindle to knuckle
- 1987-1992 Knuckles have tension pin style calipers and 6 bolts holding the spindle to knuckle
- 1994-1996 Knuckles have two bolt style calipers and 6 bolts holding the spindle to knuckle. Also have ABS provision.
The photo below shows the difference between the typical Dana 44 TTB steering knuckle on the left, and the Dana 44HD TTB / Dana 50 TTB steering knuckle on the right. While it hay be difficult to see, the balljoint spacing is about a 1/2-inch wider on the Dana 44HD knuckle.
Dana 44 TTB Brake Rotors:
The Dana 44 TTB used (3) different style of brake rotors from 1980-1996.
1980-1986 & 1988-1993 Rotor Specifications:
- Brake Rotor Casting Type Vented
- Brake Rotor Diameter, Outer 11.720 in
- Brake Rotor Thickness, Discard 1.120 in
- Brake Rotor Thickness, Nominal 1.185 in
- Coating Bare
- Height, Overall 2.704 in
- Performance Level Standard Performance
- Packaged Weight 12.200 lb
- Wheel Bolt Circle Diameter 5.500 in
- Wheel Bolt Holes, Primary 5 Each
1987.5 – 1988 With Flange Style Locking Hubs Rotor Specifications:
- Brake Rotor Diameter, Outer: 11.720 in
- Brake Rotor Thickness, Discard: 1.122 in
- Brake Rotor Thickness, Nominal: 1.185 in
- Height, Overall: 2.975 in
- Surface Finish: Plain
- Wheel Bolt Circle Diameter: 5.500 in
1994-1996 Rotor Specifications:
- Vented or Solid Style Rotor: Vented
- Height: 2.54″
- Number Bolts/Holes: 5
- Bolt Circle Diameter: 5.5″
- Center Hole Diameter: 3.88″
- Nominal Thickness: 1.025″
- Discard Thickness: .960″
Dana 44 TTB Labeled:
Dana 44 TTB Diagrams:
1978-1998 Dana Axles Parts Manual (Dana 44 TTB Starts on Page 121)
Dana 44 TTB Maintenance Manual