D6D TRACTOR POWER TRAIN – Bevel Gear And Pinion (Direct Drive)

Adjustment Procedure For The Bearings On The Bevel Gear Shaft (3)

1. Install bevel gear shaft (3) without bevel gear (7) if the transmission is installed in the machine. Install bevel gear shaft (3) with bevel gear (7) if the transmission is removed from the machine.

2. Install bearing cage (1) with a full package of shims (2). Tighten bolts (6), without lockwashers, evenly. The thickness of a full shim pack (2) is … 3.02 to 3.18 mm (.119 to .125 in)

3. Install bearing cage (5) without shims (4).

4. Install bolts (8), without lockwashers.

5. While bevel gear shaft (3) is slowly turned, tighten bolts (8) evenly until the end play of shaft (3) is zero.

6. Use a feeler gauge and measure the distance between the flange of bearing cage (5) and the face of the bevel gear case. Measure the distance at each of bolts (8) around cage (5). Make sure the measurement of each bolt is the same.

7. Remove bearing cage (5).

8. Install bearing cage (5) with an amount of shims (4) to equal the distance measured in Step 6 less … 0.13 mm (.005 in)

9. Install the nut for the steering clutch hub on bevel gear shaft (3). To check for the correct bearing adjustment, turn the bevel gear shaft at 300 to 400 RPM for 20 seconds. With a slow, steady motion, check the torque needed to turn the bevel gear shaft. The correct torque to turn the bevel gear shaft is … 3.5 to 5.0 N·m (30 to 45 lb in)

10. If the bearings need further adjustment, rotate the bevel gear shaft a minimum of 20 seconds at 300 to 400 RPM after each adjustment and before measuring the torque required to turn it.

Adjustment Of The Free Movement (backlash)

1. Push the pinion as far toward the front of the transmission as possible.

2. Install a block of wood between the pinion and bevel gear case to keep the pinion from turning.

3. Install a dial indicator so that the indicator tip is on one tooth of bevel gear (7).

4. Move bevel gear (7) backward and forward. The free movement (backlash) is the difference in the values read on the dial indicator.

5. Measure the backlash at four points around the bevel gear to find the location of the smallest backlash.

NOTE: Make sure the pinion is held as far toward the front of the transmission as possible to get the correct measurement.

6. The correct free movement (backlash) is … 0.20 + 0.10 – 0.08 mm (.008 + .004 – .003 in)

7. If the smallest amount of free movement (backlash) is too large, remove some shims (2) from behind bearing cage (1). Install the shims (that were removed) behind bearing cage (5).

8. If the smallest amount of free movement (backlash) is too small, remove some of shims (4) from behind bearing cage (5). Install the shims (that were removed) behind bearing cage (1).

NOTE: The adjustment of the bearings for the bevel gear shaft will not change by the movement of the shims from one side to the other if the total thickness of the shims does not change.

Illustration A

Illustration B

Illustration C

Adjustment Of Tooth Contact Pattern

After the free movement (backlash) and bearing adjustments have been made, check the correct area of tooth contact between the bevel gear and pinion. Do the procedure that follows:

1. Put a small amount of Prussian blue, red lead or paint on the bevel gear teeth.

2. Turn the pinion shaft in both directions and check the marks made on the bevel gear teeth.

3. See Illustration A for the marks of the correct tooth contact.

4. If the marks on the bevel gear look like the marks in Illustration B, use the following procedure.

a. Remove some of shims (2) from the bearing cage (1) for the pinion.

b. After removing some of the shims, check the backlash again.

c. Check tooth contact again.

5. If the marks on the bevel gear teeth look like the marks in Illustration C, use the following procedure:

a. Install more of shims (2).

b. After installing more of the shims, check the backlash again.

c. Check the tooth contact again.

NOTE: Several adjustments may be necessary before getting correct tooth contact. The backlash must be correct before tooth contact can be checked.

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