Transfer gearbox

Two types of transfer gearboxes have been used. One type is the mechanical shift (dog clutch) shown in Fig. 1. The other type is equipped with an elec­tric/hydraulic operated multiple disc clutch (Fig. 2). 



Fig. 1—Exploded view of drive shaft and mechanical shift (dog clutch) transfer case used on some models.
1.Front coupler  2.Front drive shaft  3.Ball bearing  4.Cap screws  5.Rear coupler  6.Snap ring  7.Retainer  8.Output shaft  9.Oil seal  10.Snap ring  11.Roller bearing 12.Shaft 13.Selector collar  14.Gear  15.Cup plug  16.Roll pin  17.Roll pin  18.Drain plug  19.Snap ring  20. Plug  21. Spring  22. Spring  23. Ball  24. Housing 25. Gasket  26. Thrust washer  27. Roller bearing  28. Pads  29.Bolt  30. Yoke  31. Spring  32.Lever (L.H.)  33. Nuts  34. Shaft  35. Roll pins  36. Lever (R.H.) 37.  "O" ring



Fig. 2—Exploded view of front drive shaft and transfer case with electric/hydraulic multiple disc clutch used on some models.
1.Front coupler  2.Front drive shaft  3.Bail bearing  4.Cap screws 6.Snap ring  7.Retainer  8.Output shaft  9.Oil seal  10.Snap ring  11.Roller bearing  12.Shaft 13.Rings  14.Ring  16. Washer  16.Roller bearing  17.Drain plug  18.Housing 19.Solenoid valve  20.Socket head  21. Gasket  22. Cover  23. Cap screw (4)  24. Snap ring &. Rear coupler  25. Carrier  26. End plate (Internal) 27. Inner spline discs  28. Outer spline discs  29. Variable thickness plate  30. Constant (external)  thickness plate  31. Snap ring  32. Gear  33. "O" ring (3)  34. Pressure pins (3)  35. Piston  36. Seal ring (inner)  37. Seal ring (outer)  38. Belleville spring  39. Spacer ring screw (2)  40. Snap ring

The clutch is engaged by three Belleville springs when hydraulic power is switched OFF. When hy­draulic power is switched ON, the piston collapses the Belleville springs and clutch is disengaged.

Models With Mechanical Shift

Overhaul
Remove the trans­fer gearbox, first remove drive shaft shield and front drive shaft as outlined. Then, remove plug (18—Fig 1) and drain oil. Drive out roll pin and remove shift lever from gearbox Place a floor jack un­der gearbox, unbolt and carefully lower gearbox from tractor. Place the gearbox in a soft jawed vise with output shaft pointing upward. Remove snap ring (6) and re­tainer (7). Withdraw output shaft (8) and pry out oil seal (9). Remove snap ring (10), then using an internal puller and slide hammer or equivalent, remove shaft (12) from gearbox. Re­move bearing (11) from shaft. Remove selector col­lar (13), gear (14), thrust washer (26) and inner race of bearing (27), Remove pads (28), then remove wash­ers (33), spring (31), bolt (29) and washers from both sides of shift fork (30). Drive the four roll pins (35) into shaft (34) and withdraw shaft. Remove left le­ver (32), detent ball (23), shift fork (30), right lever (36) and its detent ball as shaft is removed. Remove snap rings (19), plugs (20) and springs (21 and 22) from both sides of gearbox. Remove cup plugs (15) and drive roll pins (16 and 17) from both sides. Drive roll pins (35) out of shaft (34). Clean and inspect all parts and renew as necessary. If roller bearing (27) shows excessive wear or other damage, use internal puller  to remove.

When reassembling, use new ' 'O'' ring (37) and oil seal (9), then reassemble by reversing the disassem­bly procedure. With reassembly completed, adjust bolts and nuts (29 and 33) until shift pads (28) on yoke are centered in selector collar. Clearance should measure 0.0394 inch (1.0 mm) on each side when correctly adjusted. Lock the nuts together.
Reinstall transfer gearbox, using new gasket (25— Fig. 1). Tighten retaining bolts to a torque of 90 ft.-Ibs. (120 N*m). Install shift lever and secure with roll pin. Reinstall front drive shaft and drive shaft shield as outlined. Check transmission oil level and refill as necessary.

All Models With Electric/Hydraulic Shift

Overhaul
To remove the trans­fer gearbox, first remove drive shaft shield and front drive shaft. Remove plug (17—Fig. 2) and drain oil. Disconnect electrical conduit pipe from union near solenoid cover, then remove the union. Remove solenoid cover cap screws (23) and re­move cover (22) and gasket (21). Disconnect wire from solenoid (19). Disconnect and cap the hydrau­lic line at left rear of transfer gearbox. Place a floor jack under the gearbox, unbolt and carefully lower gearbox from tractor.

Place the gearbox in a soft jawed vise with output shaft pointing upward. Remove snap ring (6) and retainer (7). Withdraw output shaft (8) and pry out oil seal (9). Remove snap ring (10) and insert blocks above clutch carrier (25). Remove disc clutch assembly (24 through 40). Remove thrust washer (15) and in­ner race of bearing (16). Use the internal puller to remove the bearing. Remove roller bearing (11) and seal rings (13 and 14) from shaft (12). Remove socket head screws (20) and withdraw solenoid valve (19).
To disassemble the clutch assembly, place unit in a press with Belleville springs up. Use a cutaway short piece of pipe to allow removal of snap ring (40). Then, remove spacer ring (39) and Belleville springs (38). Invert the unit and remove snap ring (24), end plate (26), clutch discs (27 and 28) and plates (29 and 30). Remove clutch piston (35) by tapping the ends of pressure pins (34) alternately. Remove seal rings (36 and 37) from piston and "O" rings (33) from pres­sure pins (34). Clean and inspect all parts and renew any showing excessive wear or other damage.

Use all new "O" rings, seal rings, oil seals and gaskets when reassembling. Reassemble by reversing the disassembly procedure keeping the following points in mind: Install piston seal rings (36 and 37) with larger diameter of the tapered rings toward pressure side of piston. Install new "O" rings (33) on pressure pins (34) and put grease on "O" rings and on foot plate of pins. Install pressure pins in groove of piston, lubricate seal rings and install piston with pins into gear cylinder (32). Install three Belleville springs (38) against piston and spacer ring (39) with chamfered side toward Belleville springs. Compress springs and install snap ring (40). Turn unit over and install constant thickness 0.157 inch (4.0 mm) end plate (30). Install one medium variable thickness 0.213 inch (5.4 mm) plate (29). Install shaft (12) tem­porarily to align clutch plate inner splines. Then, starting with an outer splined disc (28) and followed by an inner splined disc (27), alternately install all 17 discs. Install end plate (26). Press inward on clutch plates to compress Belleville springs and install snap ring (24). Continue applying approximately 2250-3375 lbs. (10000-15000 N) with press on clutch plates and measure distance from top of clutch carrier to end plate. Record the measurement. Completely re­lease all pressure and again measure distance from top of carrier to end plate. Subtract the second meas­urement from the first measurement to obtain clutch disc clearance which should be within the limits of 0.031-0.071 inch (0.8-1.8 mm). If clearance is not with­in the limits, disassemble and change thickness of variable thickness plate (29). Plate is available in 14 thicknesses from 0.157 to 0.268 inch (4.0 to 6.8 mm). When installing seal rings on shaft (12), make certain ends of seals are hooked together. Install three new "0" rings on solenoid valve (19), lubricate the "O" rings and install solenoid valve.

When unit is reassembled, use new gasket, reinstall transfer gearbox and tighten retaining bolts to a torque of 90 ft.-lbs. (120 N-m). Connect electric wire to solenoid and hydraulic line to gearbox. Use new gasket (21) and install cover (22). Check transmission oil level and refill with Hy-Tran Plus oil.
Before installing front drive shaft, check the slip torque of the gearbox clutch as follows: Place trans­mission in first gear and low range and apply park brake. Using a torque wrench and special tool on end of output shaft, check clutch slip torque. If unit was assembled with new clutch parts, clutch should slip at 654 ft.-lbs. (887 N-m). If used clutch parts were used, clutch should slip at 594 ft.-lbs. (806 N-m). If slip torque is considerably lower, Belleville springs may be weak and should be renewed.
Reinstall front drive shaft and drive shaft shield as outlined.

Tie rods and Toe-in (Models With Front Drive Axle)

Toe-in must be 0-3/16 inch (0-5 mm) and is ad­justed by turning the threaded studs between steer­ing cylinder rod and tie rod ends. Both sides must be adjusted equally.