Differential and bevel drive gears

To remove the front differential assembly, securely block rear wheels and apply park brake.
Although most work on the front drive axle assembly can be accomplished without removing the complete axle assembly, some mechanics pre­fer to remove the axle assembly when overhauling the differential and bevel drive pinion.


Fig. 1—View of front support and relative components used on four-wheel drive models. 
1.Foam seal  2.Front cover  3.Front support  4.Lower air baffle  5.Spring pin dowels  6.Cap screws  7."O" rings  8.Pivot bearings  9. Bearing cap (front) 10.Bearing cap (rear)  11.Cap screw   12.Washer  13.Cap screw  14.Spring pin dowel

Unbolt and remove drive shaft shield and front drive shaft assembly as outlined. Dis­connect steering cylinder lines and cap or plug all openings. If so equipped, unbolt and remove front weights and weight bracket. Raise front of tractor un­til front wheels are off the floor. Support tractor un­der oil pan using tractor splitting tool or equivalent. Support each end of axle housing with jack stands. Unbolt and remove front wheels. 


Fig, 2—Exploded view of wheel hub and planetary, swivel housing and axle shaft and left axle housing and relative components. Except for axle housing, right side is similar.
1.Wear ring  2.Scraper ring  3.Oil seal  4.Rearing assemblies  5.Lug bolt  6.Hub  7.Lug nut  8.CT ring  9.Hollow dowel pin  10.Ring gear  11.Thrust washer 12.Stub shaft (sun gear)  13.Snap ring  14.Shim  15.Planetary carrier  16.Socket head screw  17.Drain/level plug  18.Seal ring  19.Angle rings  20.Planetary gear 21.Roller bearing  22.Snap ring  23.Cap screw  24.Axle shaft   25.Snap rings   26.Double U   27.Oil seal   28.Sleeve bushing   29.Cap screw   30.King pins  31.Shims (upper & tower)  32.Swivel housing  33.Lube fitting   34.Breather vent  35.Air bleed screw  36.Axle housing (L.H.)  37.Cap ring "O" ring  38.Bearing assy.  39.Cup plug  40.Sleeve bushing  41.Oil seal  42.Level plug "O" rings  43.Drain plug

Discon­nect tie rod ends from arms on swivel housings. Re­move drain plug (45—Fig. 2) and drain oil from axle housing. Attach a sling and hoist to planetary hub. Unbolt and remove upper and lower king pins (30) with bearing cones (39). Keep shims (31) with respec­tive king pins. Remove planetary, swivel housing and axle shaft from each end of axle housing. Place a floor jack under center of axle housing Unbolt axle pivot bearing caps (9 and 10—Fig. 1), lower axle as­sembly and remove from under tractor. Unbolt and remove right axle housing (23—Fig. 3) from left axle housing (5). Then, remove differential assembly from left axle housing.



Fig, 3—View of axle housings and exploded view of Refer also to Fig. 16.
1.Carrier bearing assy. 2.Shim washer 3.Breather vent 4.Air bleed screw 5.Axle housing (L.H.) 6.Sleeve bushing 7.Oil seal 8.Oil level plug 9.Drain plug 10.Lock plate 11.Cap screw 12.Ring gear 13.Thrust washers 14.Side gear (R.H.) 15.Differential pinions 16.Side gear (L.H.) 17.Differential case 18.Pinion shaft 19.Roll pin 20.Roll pin (large) 21.Roll pin (small) 22.Cap screw 23.Axle housing (R.H.) 24."0" ring 25.Shim spacer 26.Carrier bearing 

Two types of differential units are used. Type One (without limited slip clutch) Is shown In Fig. 3, Type Two shown In Fig. 5 is equipped with limited slip self-locking clutch discs.
To disassemble Type One differential, refer to Fig. 15 and using a suitable puller remove bearing cones (1 and 26). Pry off lock plate (10) and remove cap screws (11). Remove ring gear (12) from differen­tial case (17). Remove roll pin (19) and pinion shaft (18), then separate thrust washers (13), differential pinions (15) and side gears (14 and 16) from case. Remove roll pins (20 and 21). Remove bearing cups (1 and 26) and shim spacers (2 and 25) from axle hous­ings (5 and 23). Clean and inspect all parts for exces­sive wear or other damage and renew as necessary. Ring gear (12) and bevel drive pinion (8—Fig. 4) are available only as a matched set. Refer to paragraph 15 for R&R of bevel drive pinion. When reassembling Type One differential, refer to Fig. 3 and install thrust washers (13), side gears (14 and 16) and differential pinions (15) in case (17). Install pinion shaft into case and through differential pinions (15). Secure shaft with roll pin (19). Screw two guide studs into case (17) and press ring gear (12) onto the case.


Fig, 4—Exploded view of bevel drive pinion and relative components.
1.Lock plate  2.Nut  3.Oil seal  4.Outer bearing assy.  5.Spacer ring  6.Shim spacer  7.Inner bearing  8.Bevel drive pinion shaft

Install roll pins (20 and 21) and cap screws (11). Tight­en cap screws to a torque of 51 ft.-lbs. (69 N*m), then press lock plate (10) over bolt heads. Heat bearing cones (1 and 26) in a bearing oven to a temperature of 250° F (120° C) and install on differential assembly.


Fig,  5—Exploded  view of limited slip  differential

To disassemble the Type Two differential, use a suitable puller and remove carrier bearing cones. Pry off lock plate (10—Fig. 5) and remove cap screws (11). Separate ring gear (12) from differential case (17). Remove roll pin (19) and pinion shaft (18), then remove differential pinions (15), thrust washers (13), side gears (14 and 16) with thrust discs (1), friction plates (2) and friction discs (3). Remove roll pins (20 and 21). Remove bearing cups (1 and 26—Fig. 3) and shim spacers (2 and 25) from axle housings (4 and 23). Clean and inspect all parts for excessive wear or other damage and renew as necessary. Ring gear (12—Fig. 5) and bevel drive pinion (8—Fig. 4) are available only as a matched set. Refer to paragraph 15 for R&R of bevel drive pinion. When reassembling, install one 0.118 inch (3.0 mm) thick thrust disc (1-Fig. 5) on each side gear, then starting with a friction plate (2) alternate with friction disc (3) until five friction plates and four friction discs are in place on each side gear. Install side gear (16) assembly into differential case (17). Install thrust washers (13) and differential pinions (15). Install pinion shaft (18) through differen­tial pinions and secure with roll pin (19). Then, in­stall side gear (14) assembly in differential case. With differential case standing on carrier bearing end, ap­ply light hand pressure on the plates and measure the distance between friction plate and end. Record measurement and check the clearance on opposite side, using a feeler gage through hole. Clearance (end play) of friction plates should be 0.0039-0.0078 inch (0.1-0.2 mm) for each side. If measurements are not correct, change thickness of thrust plate (1—Fig. 5) as needed. Thrust plates are available in thick­nesses of 0.110,0.114, 0.118, 0.122, 0.126 and 0.130 inch (2.8, 2.9, 3.0, 3.1, 3.2 and 3.3 mm). Screw two guide studs into case (17) and press ring gear (12) onto case. Install roll pins (20 and 21) and cap screws (11). 

Tight­en cap screws to a torque of 51 f t.-lbs. (69 N-m), then press lock plate (10) over bolt heads. Heat carrier bearing cones in a bearing oven to a temperature of 250° F (120° C) and install on differential assembly.
To remove the bevel drive pinion (8—Fig. 4), remove lock plate (1). Remove nut (2), then drive the bevel pinion shaft into left axle housing. Remove oil seal (3), outer bearing cone (4) and spacer (5). Drive shim spacer (6) and inner bearing cup (7) from hous­ing, then remove outer bearing cup (4). Using a suita­ble puller, remove inner bearing cone (7) from bevel pinion shaft. Clean and inspect all parts and renew as necessary. Bevel drive pinion (8) and ring gear (12—Fig. 15 or 16) are available only as a matched set.
Before reinstalling bevel drive pinion, adjust differential carrier bearing preload as follows: Install a 0.47 inch (1.2 mm) thick shim spacer (2—Fig. 3) in left axle housing (5) and install left carrier bear- ing cup (I). Install differential assembly in left axle housing. Hold right carrier bearing cup on bearing cone and measure distance between outer edge of cup and left axle housing flange. Measure distance between right axle housing flange and carrier bearing seat (shoul­der). Subtract the first measurement from the sec­ond measurement. Select a shim washer (25—Fig. 3) with thickness equal to the difference between the two measurements. Shim washers are available in twenty thicknesses from 0.020-0.071 inch (0.5 to 1.8 mm). 

Install the selected shim washer (25) and car­rier bearing cup in right axle housing. Remove differential assembly and wrap a cord around differential case. Attach a spring scale to loose end of cord. Reinstall differential assembly with spring scale protruding through bevel pinion shaft opening. Install right axle housing assem­bly and secure with four cap screws (22—Fig. 3) spaced at 90 degree intervals. Tighten the four cap screws to a torque of 44-52 ft.-lbs. (60-70 N-m). Pull on spring scale and check rolling resistance of differential assembly. Amount of pull on scale should be between 4,4 and 16.5 lbs. (2.0 and 7.5 kg). If not, remove right axle housing, remove carrier bearing cup (26) and install a thicker shim washer (25) to in­crease or a thinner shim washer to decrease preload on bearings. Reassemble and reinstall right axle hous­ing and recheck preload.


Fig. 6—Measure distance "A" between end of bevel drive pinion bore and differential case

When preload is correct, measure distance "A" from end of bevel drive pinion bore to differential case as shown in Fig. 6. Record distance "A". Re­move right axle housing and differential assembly. Install inner pinion shaft bearing cup. Hold pinion shaft bearing cone in position with a flat steel plate and measure distance.  Shim spacers (6) are available in thicknesses of 0.035 to 0.059 inch (0.9 to 1.5 mm) in 0.002 inch (0.05 mm) increments.

Using a bearing oven, heat inner bearing cone (7) to a temperature of 250° F (120° C) and install on level pinion shaft. Install outer bearing cup (4) in pin-inn housing until seated. Install special tool measuring ring on pinion shaft so dowels are away from bearing. Install pinion shaft assembly into pin­ion housing. Heat bearing cone (4) in a bearing oven to a temperature of 250° F (120° C) and install on pinion shaft until seated in bearing cup. Install and tighten nut (2) on pinion shaft until a slight drag is felt when rotating bevel drive pinion. Wrap a cord around pinion shaft and attach a spring scale to end of cord. Check rolling resistance of pinion shaft and adjust by progressively tightening the nut. Rolling re­sistance must be 17.6-30.8 lbs. (8.0-14.0 kg) with new bearings or 11.0-17.6 lbs. (5.0-8,0 kg) with used bear­ings. Remove the pinion shaft and remove the meas­uring ring from pinion shaft. Using a micrometer, measure distance. Select a spacer ring (5—Fig. 4) equal to the distance. Spacer rings are available in fifteen thicknesses from 0.433 to 0.488 inch (11.0 to 12.4 mm) in increments of 0.0039 inch (0.1 mm). Install selected spacer ring on bevel pinion shaft and install the assembly in pin­ion housing. Heat outer bearing and install on pin­ion shaft until seated in bearing cup. Install and tight­en pinion shaft nut to a torque of 384 ft.-lbs. (520 N-m). Again, check rolling resistance of the pinion shaft. If rolling resistance is not correct, disassem­ble and select a thicker spacer ring to increase or thinner spacer ring to decrease rolling resistance, Reinstall pinion shaft assembly.

Apply engineers blue to both sides of some of the ring gear teeth. Install differential and right axle housing. Install four cap screws (22—Fig. 3) at 90 de­gree intervals and tighten them to a torque of 44-52 ft.-lbs. (60-70 N*m). Rotate pinion shaft several times, then working through the drain plug opening, use a dial indicator and check ring gear to pinion backlash which should be 0.003-0.009 inch (0.07-0.22 mm). If backlash is less than 0,003 inch (0.07 mm), remove shims from right side and move them to left side. If backlash is more than 0.009 inch (0.22 mm), remove shims from left side and move them to right side. Un­bolt and remove right axle housing and differential assembly. Check the tooth contact pattern on ring gear teeth and compare with patterns shown in Fig, 7. Views "A" and "B" shown correct tooth contact patterns. Views "C" and "D" show that pinion must be moved inward. Views "E" and "F" show that pin­ion must be moved outward. Readjust as necessary.


Fig. 7—Views of bevel ring gear tooth contact patterns

With ring gear and bevel drive pinion correctly ad­justed, install differential assembly, lubricate and in­stall "O" ring (24—Fig. 3) and install right axle hous­ing (23). Install and tighten cap screws (22) to a torque of 44-52 ft.-lbs. (60-70 N-m).
Remove pinion nut (2—Fig. 4) and after applying a light coat of sealant to outer surface of oil seal (3), install oil seal with lip to inside. Install nut and tight­en to a torque of 384 ft.-lbs. (520 N-m). Install new lock plate (1) over nut, then using a hammer and small punch, peen edge of plate into pinion shaft splines.
Install new oil seals (7—Fig. 3) if necessary, then reassemble and reinstall front drive axle by revers­ing disassembly and removal procedures. Fill axle housing to level plug opening with SAE 90 EP gear oil. Refill capacity is 4.75 U.S. quarts (4.5 L).