Model 44-IFS
TOTAL DIFFERENTIAL CASE ENDPLAY INSPECTION
1. Attach ring gear to differential case using new bolts, then tighten bolts alternately and evenly to: grade 8 bolts 60 ft lb, and grade 9 bolts 90 ft lb.
2. Clean trunnions on differential and install bearings onto differential case. Remove all burrs and nicks from hubs so bearings rotate freely.
Fig. 6 Total Differential Case Endplay Inspection:
3. Place differential case into carrier (without pinion). Differential case should move freely in carrier assembly. Position a suitable dial indicator against differential case flanges. Locate tip of indicator on flat surface of one ring gear bolt. Force differential case toward dial indicator as far as possible and zero dial indicator with force still applied. Dial indicator should have a minimum of 0.350 inch travel. Force differential case away from dial indicator as far as it will go. Repeat this procedure until same reading is obtained. Record dial indicator reading as measurement "A" on a work sheet for calculating ring gear backlash and differential bearing preload shims. This reading indicates amount of shims needed behind differential side bearings to take up total clearance between differential bearing cup and carrier. This reading will be used during "Pinion & Ring Gear Backlash Inspection".
4. Remove differential case from carrier. Do not remove differential case bearings at this time.
DRIVE PINION INSTALLATION
Two separate adjustments affect drive pinion and ring gear tooth contact: pinion depth and pinion to ring gear backlash.
Fig. 16 Drive Pinion Installation.:
Pinion depth is controlled by a pinion locating shim pack installed between drive pinion inner bearing cup and carrier housing. This shim pack and inner oil slinger and oil baffle controls the position of the pinion. Adding shims moves pinion toward ring gear and removing shims moves pinion away from ring gear.
Fig. 8 Ring & Pinion Identification:
Pinion to ring gear backlash is controlled by preload shims located between the differential bearing cup and carrier. On the button of each drive pinion is marked a plus (+), a minus (-) or a zero (0). These markings indicate the position for each gear set. The position is determined by amount of shims between inner pinion bearing cup and carrier bearing bore. Any pinion depth change is made by changing amount of shims.
Fig. 10 Drive Pinion Adjusting Shim Thickness Chart (Metric):
If the original gear set is being reused, measure the slinger, baffle and each shim separately and add each shim measurement to total original measurement. Replace old shims with new shims that equal this measurement, if necessary. If a new gear set is being used, notice the plus (+), minus (-) or zero (0) etchings on both original and new drive pinion and add or subtract shims according to charts to compensate for differences between old and new pinion.
DEPTH GAUGE INSPECTION
Fig. 17 Depth Gauge Tool Selection.:
1. Refer to chart for correct tool usage on particular axle assemblies. If any gauge surfaces become nicked, high spots must be removed with a medium India oilstone to ensure no erroneous readings are obtained.
2. Install oil baffle into inner bearing cup bore in carrier.
Fig. 13 Inner & Outer Pinion Cup Installation Tools:
3. Install inner and outer pinion cups using suitable tools.
4. Place a new inner pinion bearing over proper aligning adapter and insert into pinion bearing retainer assembly. Place outer pinion bearing into bearing cup in carrier and assemble handle onto screw and hand tighten. Note 3/8 inch square drive in handle to be used for obtaining proper pinion bearing preload.
5. Center proper gauge tube into differential bearing bore, install bearing caps and tighten to 80-90 ft lb. To preload bearings, torque handle to 20-40 inch lb.
6. Using suitable feeler gauges, select thickest feeler gauge that will fit between gauge tube and gauge block. Insert feeler gauge directly along gauge block to ensure a correct reading. Feeler gauge should fit between gauge tube and gauge block with only a slight drag.
7. After correct feeler gauge feel is obtained, thickness of feeler gauge used to obtain slight drag-type feel is the thickness of shims required, provided new pinion gear is marked with a zero (0). If new pinion gear is marked with a plus (+) reading, the plus (+) amount stamped on pinion gear must be subtracted from thickness dimension obtained in preceding step. If new pinion gear is marked with a minus (-) reading, the minus (-) amount stamped on pinion gear must be added to thickness dimension obtained in preceding step. Also, you must use same new inner pinion bearing that was used to obtain this dimension.
Fig. 14 Bearing Installation On Drive Pinion:
8. Measure shims with a micrometer to verify size, then place oil slinger, if required, onto pinion and press on bearing. If a baffle and/or slinger is used, replace with a new one upon assembly and measure as part of the shim stack.
9. Lubricate ends of outer pinion bearing rollers with a suitable high-temperature lubricant.
BEARING CUP INSTALLATION
1. Clean bore and, if installed, remove cup. Place oil baffle first and required amount of shims in inner pinion bearing bore and drive inner pinion bearing cup in place using suitable pinion bearing cup replacer and forcing screw. Use care not to cock cup.
2. Place outer pinion cup into carrier and drive in place. Draw cups into bore.
3. Lubricate ends of outer pinion bearings rollers. Install outer bearing cone into place in outer bearing cup.
4. Install inner bearing cone and slinger onto pinion. Drive bearing on pinion shaft until fully seated using suitable pinion bearing replacer.
DRIVE PINION PRELOAD INSPECTION
1. Install pinion into carrier, then new preload shims over pinion.
2. Install outer pinion bearing and oil slinger.
3. Coat drive pinion oil seal with suitable hypoid gear lubricant or equivalent, then install drive pinion oil seal using suitable oil seal replacer. After installation, ensure garter spring did not pop out. If garter spring pops out, remove and replace seal.
4. Install yoke using tool No. T83T-4851-A, or equivalent, then install washer and nut and torque to 200-220 ft lb.
5. Place an inch-pound torque wrench on pinion nut and check pinion rotational tightening. Rotational torque should be 20-40 inch lb.
6. To increase preload, remove shims. To decrease preload, add shims.
PINION & RING GEAR BACKLASH INSPECTION
1. Attach ring gear to differential case using new bolts, then tighten bolts alternately and evenly to: grade 8 bolts 60 ft lb, and grade 9 bolts 90 ft lb.
2. Place differential case into position in carrier (differential case bearings should still be installed).
Fig. 6 Total Differential Case Endplay Inspection:
3. Force differential case away from drive pinion gear, until it is completely seated against cross bore face of carrier. Position a dial indicator so indicator tip rests on a ring gear bolt head. Zero dial indicator.
4. Force ring gear against pinion gear. Rock ring gear slightly to ensure gear teeth are in contact, then force ring gear away from pinion gear, ensuring dial indicator returns to zero. Repeat this procedure until dial indicator reading is the same. This reading should be recorded as measurement "B" and reveals amount of shims necessary between differential case and differential bearing on ring gear side.
5. Assemble shim pack for ring gear side to measurement "B."
6. Subtract measurement "B" from measurement "A" obtained in "Total Differential Case Endplay Inspection" in this section to obtain measurement "C." Measurement "C" equals amount of shims required between differential case and bearing on side opposite of ring gear.
7. Assemble shim pack for side opposite of ring gear to measurement "C" plus (+) 0.010 inch.
8. Remove differential case from carrier, then the bearings from case.
9. Place required amount of shims on hub of ring gear side of differential case, then install bearing and drive bearing onto hub using a suitable differential side bearing replacer.
10. Place required amount of shims on hub of differential case opposite of ring gear side, then install bearing. Place a suitable step plate on ring gear side bearing to protect bearing, then drive bearing opposite of ring gear side onto hub using differential side bearing replacer.
11. Install differential bearing cups onto bearings.
12. Mount spreader tool No. 4000-E and tool No. T80T-4000-B, or equivalents, onto carrier assembly.
13. Position a dial indicator onto carrier, then spread housing.
NOTE: Do not spread housing more than 0.015 inch.
14. Install differential case into carrier. If necessary, use a rawhide or plastic hammer to seat case in carrier bore. With partial and non-hunting/partial ring gear and pinion sets, align marks on ring gear and drive pinion, if applicable. Use care not to nick teeth of ring gear or pinion.
15. Remove spreader and dial indicator.
16. Install bearing caps and bolts, ensuring letters or numbers stamped on caps correspond in both position and direction with letters or numbers stamped into carrier, then tighten bolts.
Fig. 15 Ring Gear & Pinion Backlash Inspection:
17. Install dial indicator on case.
18. Check ring gear and pinion backlash at three equally spaced points on ring gear. Back lash tolerance is 0.005-0.009 inch and cannot vary more than 0.003 inch between the three points.
19. If backlash is high, ring gear must be moved closer to pinion by moving shims to ring gear side from opposite side.
20. If backlash is low, ring gear must be moved away from pinion by moving shims from ring gear side to opposite side.
21. Install right hand slip yoke and stub shaft.
22. Apply a continuous bead of RTV silicone sealant 1/8 to 1/4 inch high and 1/4 to 1/2 inch wide on mating surfaces of carrier mounting face support arm, then mount carrier assembly to left hand axle arm, using two guide pins. Install mounting bolts and tighten to 30-40 ft lb. Use new bolts with encapsulated adhesive or wire brush old bolts and apply thread-locking compound part No. E0AZ-19554-A, or equivalent.
23. Allow sealant one hour cure time prior to filling carrier with proper amount of specified lubricant.