Assembly
DIFFERENTIAL CASE1. Install thrust washers onto side gears and position into differential case.
2. Install thrust washers onto pinions and mesh them with the side gears.
3. Rotate side gears to position the pinions in the differential case.
4. Install pinion shaft, aligning roll pin holes in shaft and case.
5. Install pinion shaft roll pin.
6. Position ring gear onto differential case and install new mounting screws. Torque screws progressively in a crisscross pattern to draw the ring gear evenly on the case. Torque screws to 58-62 ft. lbs. on Scorpio models, or 55-66 ft. lbs. on XR4Ti models.
DIFFERENTIAL SIDE BEARING CONES
1. Using tool T85M-4221-A or equivalent, press new bearings onto differential case hubs.
2. Ensure bearings are completely and evenly seated in case hubs.
PINION INNER BEARING
Do not install a new bearing at this time. The bearing will be used with the pinion depth gauge tools during axle assembly.
PINION BEARING CUPS
1. Position a standard 2 mm pinion depth shim in the inner bearing cup bore.
2. Lubricate bearing cup bore.
3. Install inner bearing cup into bore using the following tools:
a. Pinion bearing cup replacer tool T85M-4616-A. Position this tool against the inner cup.
b. Pinion bearing cup replacer tool.
c. Draw bolt T75T-1176-A or equivalents.
AXLE ASSEMBLY
Fig. 3 Installing Depth Tools:
1. Lubricate pinion bearings with suitable grease.
2. Assemble pinion bearings and dummy pinion depth tools into rear axle case as shown in Fig. 3. Ensure gauge screw is tight in the gauge disc before assembling the tool.
3. Hold gauge disc stationary and gradually tighten the tool handle until a rolling torque of 14-18 inch lbs. is measured at the pinion depth tool handle. Before conducting the rolling torque check, turn tool shaft ten times to seat the bearings. Any time the tool is loosened or tightened, rotate the pinion ten times before another rotational torque check is made.
4. Position pinion depth gauge tool tube T85M-4020-A1 or equivalent into case. Ensure tube gauging surface is aligned with gauge disc, then install bearing carriers. The bearing carriers must be installed in their original case bores and without the O-ring seals.
5. Thread the bearing carriers evenly into the case. When the carriers contact the gauge tube, snug them down to remove all endplay from the tube. The carriers are properly tightened when a moderate amount of effort is required to turn the gauge tube by hand.
6. From the available selective pinion depth shims, determine the clearance between the gauge tube and gauge disc. The correct shim thickness has been determined when a slight drag is felt between the shim and gauging surfaces.
7. The clearance check in step 6 has determined the pinion depth shim thickness for a nominal or zero variance pinion. To determine if this is the correct shim thickness, inspect the pinion shaft for a pinion variance marking and proceed as follows:
a. If the pinion shaft does not have a variance marking, a pinion variance calculation is not necessary.
b. If the pinion shaft has a minus pinion variance marking (1 to 3), measure the shim from step 6 with a micrometer to determine its thickness. From this measured thickness, add .0004 inch (.01 mm) for a minus 1 marking, .0008 inch (.02 mm) for a minus 2 marking or .0012 inch (.03 mm) for a minus 3 marking depending upon the pinion variance marking.
c. If the pinion shaft has a positive pinion variance marking (+1 to +3), measure the shim from step 6 with a micrometer to determine its thickness. From this measured thickness, subtract .0004 inch (.01 mm) for a positive 1 marking, .0008 inch (.02 mm) for a positive 2 marking or .0012 inch (.03 mm) for a positive 3 marking depending upon the pinion variance marking.
8. Install inner pinion bearing. Ensure pinion depth shim is in position on the pinion shaft before installing the bearing.
9. Install a new collapsible spacer onto pinion shaft.
10. Position pinion into case and install the outer bearing. Lubricate the bearings before installing the case.
11. Install the pinion nut.
12. To preload the pinion bearings, gradually tighten the pinion nut. Each time the nut is tightened, check the pinion shaft rolling torque (bearing preload), using an inch lb. torque wrench. Continue tightening the pinion nut in small increments until a rolling torque of 14-18 ft. lbs. is measured at the pinion shaft. An increasing resistance will be felt as the pinion bearing preload is increased by the action of the collapsible spacer. If the nut is tightened beyond the specified rolling torque, remove pinion and install a new collapsible spacer and repeat step 12.
13. Stake pinion nut to the pinion shaft.
14. Install pinion seal.
15. Install pinion flange and attaching nut. Torque attaching nut to 95-110 ft. lbs.
16. Position differential assembly into case.
17. Install new O-rings onto bearing carriers and position carriers into their original positions. Lubricate the bearing carrier threads and O-rings with the correct axle lubricant before installing case.
18. Using a suitable tool, turn bearing carriers into axle case until they lightly seat against the differential bearings. This seating action can be felt as the bearing carrier cups contact the differential bearings. When the bearing carrier O-rings enter the case, the turning effort will increase.
Fig. 4 Installing Dial Indicator Onto Axle Housing:
19. Mount a suitable dial indicator onto axle housing as shown in Fig. 4. Position indicator stylus to contact a ring gear tooth at a 90° angle.
20. Rock the ring gear forward and backward and note the reading on the dial indicator.
21. Thread the bearing carriers into the case in equal amounts until the dial indicator reads a backlash of .0004 inch (.01 mm).
22. After the minimum backlash of .0004 inch is set, tighten the bearing carrier on the differential side of the case an additional four to five teeth of the carrier to preload the bearings. If steps 18 through 22 have been correctly done, the correct amount of backlash .004-.007 inch (.10-.17 mm) should now exist between the pinion and ring gear assembly.
23. Install bearing carrier lock plates. Torque attaching bolts to 14-18 ft. lbs.
24. Install stub shafts.
25. From available selective C-clips, install the thickest possible clip in each stub shaft groove.
26. Coat axle housing to cover sealing surfaces with sealant E1FZ-19562-A, or equivalent. Install cover. Torque cover attaching bolts to 33-44 ft. lbs.
27. If the axle case, axle assembly or suspension crossmember has been replaced, it is necessary to determine whether a gap exists between the rear axle mounting boss and the crossmember mounting flanges. If a gap is found, selective shims must be installed to compensate for the clearance. Proceed as follows:
a. Install rear mount onto axle housing rear cover. Torque attaching bolts to 37-41 ft. lbs.
b. Lift assembly into position between crossmember flanges.
c. Install the through bolt and the four axle bolts to crossmember attaching bolts. Do not tighten the bolts.
d. Install axle housing rear mount. On Scorpio models, torque four attaching bolts to 14-18 ft. lbs. On XR4Ti models, torque two inner bolts to 37-41 ft. lbs. and four outer bolts to 37-50 ft. lbs.
e. Torque the front lower attaching bolt to 51-66 ft. lbs.
f. Torque through bolt to 51-66 ft. lbs.
g. Using a feeler gauge check clearance between crossmember flanges and rear axle mounting boss.
h. Select and install appropriate shims between the crossmember and axle.
i. Torque attaching bolts to 51-66 ft. lbs.