Dana 80

Differential Case and Ring Gear





Special Tool(s)





Material

Disassembly

All differentials





1. NOTE: Differential bearing shims are available in thicknesses of 0.762, 0.787, 0.813, 0.838, 0.864, 0.889 and 0.914 mm (0.030, 0.031, 0.032, 0.033, 0.034, 0.035 and 0.036 inch).

NOTE: If damaged, install new differential bearing shims.

NOTE: Install new differential bearings if removing them from the differential case.

Using the special tool, remove the differential bearings.
^ Wire the differential bearing shims, differential bearing cup, differential bearing, and selective outboard spacer(s) together. Note from which side they were removed (differential ring gear side or the opposite side).

2. NOTE: Use a vise with brass jaws or wood blocks.

Place the differential case in a vise.





3. CAUTION: Do not damage the anti-lock speed sensor ring when removing the differential ring gear. If removing the anti-lock speed sensor ring, discard it and install a new one.

NOTE: Always install new bolts upon assembly. Use Grade 9 bolts for all Dana rear axles.

Remove the bolts. Leave four bolts loosely assembled, 90° apart.





4. Tap each bolt head alternately with a rawhide or plastic hammer to loosen the differential ring gear. Remove the bolts and the differential ring gear.





5. If necessary, remove the anti-lock speed sensor ring with a soft-faced hammer. Discard the anti-lock speed sensor ring.








6. The Truetrac differential assembly is non-repairable. Discard the entire assembly if it is worn/damaged. For conventional or Trac-Lok differential assemblies, proceed as follows.

Conventional differential

7. NOTE: Use a vise with brass jaws or wood blocks.

Place the differential case in a vise.





8. Using a small drift, drive out the differential pinion shaft lock pin.





9. Using a drift, remove the differential pinion shaft.





10. To remove the differential side gears and the differential pinion gears, rotate the differential side gears. The differential pinion gears will turn to the opening in the differential case.
11. Remove the differential pinion gears and the differential pinion thrust washers behind the differential pinion gears.
12. Lift out the differential side gears and the differential side gear thrust washers.

Assembly

Conventional differential

1. NOTE: For Truetrac and Trac-Lok differential assemblies proceed to All differentials in this procedure.

NOTE: Use a vise with brass jaws or wood blocks.

Place the differential case in a vise.
2. Lubricate the new differential side gear thrust washers, the thrust face of the new differential side gears, the new differential pinion thrust washers, and the new differential pinion gears with grease.





3. NOTE: The best way to assemble the differential side gears and the differential pinion gears is to lubricate all parts with the specified rear axle lubricant.

Lubricate and assemble both differential side gears and differential side gear thrust washers. Hold them in place. Then, lubricate and assemble the differential pinion gears and the differential pinion gear thrust washers to hold the differential side gears in place.

4. NOTE: Rotate the differential side gears until the holes of the differential pinion gear thrust washers and the differential pinion gears line up with the holes of the differential case. If the differential pinion gears will not rotate by hand, install one of the axle shafts into the spline of the differential side gear and use a pipe wrench to turn the axle shaft.

Using a drift, line up the holes with those of the differential case.





5. Assemble the differential pinion shaft and drive on the differential pinion shaft to remove the drift. Align the lock pin hole in the differential pinion shaft with the lock pin hole in the differential case.





6. Assemble the differential pinion shaft lock pin. Peen the metal of the differential case over the differential pinion shaft lock pin in two places, 180 degrees apart, to lock it in place. Note the location of the slot in the differential pinion shaft lock pin and peen it 90 degrees apart.

Trak-Lok differential - disassembly

NOTE: When refilling the axle with lubricant, first add 0.163 L (5.5 ounces) of friction modifier.





7. Match-mark the differential case.
1 Match-mark the differential case flange (ring gear) and button (cover) halves.
2 Match-mark the differential pinion shafts and corresponding ramps.
8. If necessary, remove the differential ring gear.





9. NOTE: An axle shaft held in a vise, with the shaft splines extending not more than three inches above the vise Jaws, makes an excellent holding fixture for the differential case.

Loosen, but do not remove the bolts.
10. Place the differential assembly on a bench.





11. Remove the bolts and the button half of the differential case.





12. Remove the differential side gear, side gear ring, rear axle disc and plate kit, differential pinion gears, and the differential pinion shafts. Keep these parts in order for correct installation by placing them aside with the button half of the differential case.





13. Remove the side gear ring and the rear axle disc and plate kit from the flange half of the differential case. Keep these parts in order by placing them on the pinion flange as shown.
14. Inspect the following components:
^ The clutch plates and clutch discs for cracks, excessive wear, and distortion. Always install an entirely new rear axle disc and plate kit on both sides if discarding one or more of the clutch plates or clutch discs.
^ The differential pinion shafts and the ramp surfaces on the differential case for excessive wear or pitting.
^ The differential side gear and differential pinion gear teeth.
^ The differential side gear races that bear on the differential side gear rings.

Trak-Lok differential - assembly
15. Soak the clutch packs for 20 minutes in friction modifier before assembly.





16. Place the side gear ring on the pinion flange. Coat the rear axle disc and plate kit with lubricant and place it on the side gear ring.
^ Use rear axle lubricant or friction modifier.





17. CAUTION: After assembly, make sure that the side gear splines engage the clutch pack splines and the differential side gear is fully seated.

Install the side gear ring, the rear axle disc and plate kit, and the side gear in the flange half of the differential case.





18. NOTE: For vehicles operating at close to their GVW rating, typically emergency vehicles and vehicles equipped with a fifth wheel, there may be circumstances of continuing chatter/bumping in turns despite the installation of new parts and lubricant. In cases such as this, it is permissible to reassemble the rear axle disc and plate kit with the clutch disc adjacent to the differential side gear ring, resulting in two clutch plates together. This results in three friction surfaces instead of the normal five, lowering the torque to rotate the wheel by 40 percent.

Align the clutch pressure plate lugs, and install the side gear ring, the clutch pack, and differential side gear in the button half of the differential case.





19. CAUTION: Align the match marks made during disassembly.

Place the differential pinion shaft and differential pinion gears in the button half of the differential case.





20. CAUTION: Align the match marks made during disassembly.

Install the other differential pinion shaft and differential pinion gears in the flange half of the differential case.





21. CAUTION: Align the match marks made during disassembly.

Assemble the differential case.
1 Place the button half of the differential case onto the flange half of the differential case assembly.

2 CAUTION: The bolts must be clean and dry.

Install the bolts. Turn each one in a few threads.
3 Tighten the bolts evenly and alternately.
22. If assembled correctly, each differential pinion shaft will fit tight on its ramp. Clearance between the differential pinion shaft and the ramp must not be more than 0.254 mm (0.010 inch) and it must be equal at all four ends of the differential pinion shafts.

All differentials








23. NOTE: Align the tab on the anti-lock speed sensor ring with the slot in the differential case.

NOTE: Apply Threadlock and Sealer to the new bolts.

Align the tab in the anti-lock speed sensor ring with the slot in the differential case. Start the two bolts through the differential case flange and into the differential ring gear to make sure the differential case and the differential ring gear bolt hole align.





24. Press the anti-lock speed sensor ring on the differential case. The differential case flange acts as a pilot for the anti-lock speed sensor ring.





25. NOTE: Apply Threadlock and Sealer to the new bolt threads.

Draw up the Grade 9 bolts alternately and evenly.
26. Install the differential bearings.