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Case IH 685, 485 Tractor Range transmission - 2 WD and 4 wheel drive

To remove the bevel pinion mainshaft (2), remove snap ring (14) from groove in pinion shaft. Unbolt retaining plates (6) and move bevel pinion shaft rearward.

Remove Hi sliding collar (16), Lo-Reverse gear (15), snap ring (14) and four-wheel drive gear (13), if so equipped. Remove pinion mainshaft assembly and shims (10) from transmission case.

Measure and note thickness of shims (10) if the same bevel pinion main shaft is to be reinstalled. Using a dial indicator, measure end play of bearing housing (8) on bearings (7 and 9).

If end play is more than 0.003 inch (0,076 mm), renew the bearings as follows:

Remove snap ring (12) and spacer (11), then press bearings and housing from bevel pinion main shaft. Press new bearings (7 and 9) and housing (8) on bevel pinion while rotating the housing.

Apply pressure until a slight preload can be felt. Install spacer (11). Snap ring (12) is available in thicknesses of 0.066, 0.069, 0,072, 0.075, 0.078, 0.081, 0.084, 0.087, 0.090 and 0.093 inch (1.67, 1.75, 1.83, 1.90, 1.98, 2.06, 2.13, 2.21, 2.28 and 2.36 mm).

Select the thinnest snap ring, 0,066 inch (1.67 mm) and install in its groove. Make certain that bearing (9) and spacer (11) are tight against snap ring (12), then using a dial indicator, measure end play of housing (8) on bearings (7 and 9).

Add the end play to the thickness of installed snap ring. The result is the correct thickness of snap ring to be installed. Remove the thin snap ring and install the new one. This assembly will now have a maximum end play of 0.003 inch (0.076 mm) or a maximum preload of 0.002 inch (0.050 mm).

Fig.29

View showing distances (A, B and C) used In setting pinion position. To remove the countershaft (25), remove snap ring (18) and remove snap ring (24) from its groove in countershaft. Drive a wedge into split in spacer (22).

Move countershaft forward and remove snap ring (24), Lo gear (23), split spacer (22) and constant mesh gear (21) as countershaft is withdrawn. Remove snap ring (17), then press ball bearing from countershaft. Pump drive gear (29) is located on pto driven shaft and rides in needle bearing (27).

If necessary, countershaft needle bearing and pump gear needle bearing (27) can now be removed. Note position of needle bearings before removing. To remove the reverse idler gear (35) and shaft (32), drive out roll pin (33).

Withdraw shaft (32) and remove reverse idler gear (35) with needle bearings (34 and 37) and spacer (36), then remove thrust washers (31 and 38).

Clean and inspect all parts and renew any showing excessive wear or other damage. If bevel pinion mainshaft must be renewed, bevel ring gear (1) must also be renewed as they are available only as a matched set.

To set bevel pinion main shaft position, install bearings (7 and 9), housing (8), spacer (11) and correct snap ring (12) as outlined previously, then proceed as follows:

The mounting distance (A) from pinion bearing housing mounting face to the center line of the differential is approximately 6.600 inches (167.64 mm).

This distance may vary for each tractor. To aid in accurate installation of the pinion main-shaft, a single figure is stamped on the top face of the upper pto shaft boss.

The single figure indicates (in inches) the variation from distance (A) in steps of 0.001 inch (0.025 mm). When distance (A) is smaller, a minus sign will be shown in front of single figure.

Add or subtract the single figure to the approximate distance 6.600 inches (167.64 mm). The pinion cone mounting distance (B) is marked (in inches) on the rear face of the pinion and shows the distance this face must be from center line of differential. The distance will be approximately 4.410 inches (112.01 mm).

Stand pinion shaft on a flat surface. Measure distance from pinion face to the bearing housing mounting face. This is distance (C). Add distance (C) to the marked figure on pinion face (distance B) and subtract from the resulting (distance A).

The final figure is the correct thickness of shims (10) to be installed for correct pinion mainshaft position. The balance of reassembly is the reverse of disassembly procedures.

Fig.30. Case 685, 485, 585, 385, 885 tractors Range transmission used on 2WD and 4WD models. Note the heavy duty park brake drum (flange) on bevel ring gear

1.Bevel ring gear, 2.Bevel pinion mainshaft, 3.Cap screw, 4.Washer, 5.Lock collar, 6.Retaining plates, 7.Bearing, rear, 8.Bearing housing, 9.Bearing, front, 10.Shim, 11.Spacer, 12.Snap ring, 13.Front-wheel drive gear, 14.Snap ring, 15.Lo-Reverse gear, 16.Hi sliding collar, 17.Snap ring, 18.Snap ring, 19.Ball bearing, 20.Snap ring, 21.Constant mesh gear, 22.Split spacer, 23.Lo gear, 24.Snap ring, 25.Countershaft, 26.Countershaft needle bearing, 27.Pump drive gear needle bearing, 28.Snap ring, 29.Pump drive gear, 30.Snap ring, 31.Thrust washer, 32.Shaft, 33.Roll pin, 34.Needle bearing, 35.Reverse idler gear, 36.Spacer, 37.Needle bearing, 38.Thrust washer

Transfer lube pump

REMOVE AND REINSTALL

The transfer lube pump is located below the reverse idler gear in range gearbox. The pump furnishes oil for lubricating the Case IH 685, 485 speed transmission mainshaft and synchronizers and the ring gear and pinion.

Fig.31. Partially disassembled transfer pump and relative components

1.Lube tube, 2.Strainer, 3.End cover, 4.Pump, 5.Allen set screw, 6,Key, 7.Gear, 8.Snap ring

To remove the transfer pump, first remove all other range tractor transmission. Then, disconnect and remove lubrication tube (1). Remove snap ring (8) and drive gear (7),

Remove Allen set screw (5) through hole in bottom of rear main frame shown in Figure. Remove pump from transmission housing. Unbolt and remove strainer (2), then remove end cover (3).

Clean and inspect all parts. Internal parts of pump (4) are not available separately. Reassemble and reinstall transfer pump by reversing the disassemble and removal procedures.