Fluid Leak Checks

DESCRIPTION
Verify that oil leak is from transfer box and not main gearbox before proceeding with checks.

PRIOR TO ROAD TEST
1. Check oil level in transfer box is correct.
2. Check tightness of level and drain plugs.
3. Check breather system for blockage. To validate system pipe must be removed, inspected, rectified as necessary and reinstalled.
4. Remove all traces of oil from exterior of transfer box.

TAKE VEHICLE FOR SHORT ROAD TEST
Identify source of leaks and repair as follows.

FRONT OR REAR OUTPUT SEAL LEAKING
1. Drain oil and remove leaking output flange.
2. Inspect seal track on flange for surface damage. If damaged renew component.
3. Remove and discard oil seal.
4. Inspect seal locating bore and remove any sharp edges which may damage new oil seal.
5. Install new seal.
6. Install output flange and all other parts.
7. Add oil to correct level into gearbox.

COVER PLATE SEALANT LEAKING
1. Drain oil and remove leaking cover plate.
2. Remove all traces of joint sealant from both joint faces.
3. Degrease all components and apply a thin film of Hylomar sealant, to both joint faces.
4. Apply thread sealant to bolts which come into contact with gearbox oil.
5. Install cover plate.

CAUTION: Care must be taken not to overtighten fixings.

LEAK BETWEEN MAIN AND TRANSFER GEARBOXES
1. Site vehicle onto a ramp [hoist].
2. Select neutral in transfer box and select 4th gear in main gearbox.
3. Run engine at 2000 rpm with clutch/drive engaged.
4. Observe joint between main and transfer boxes.
5. If oil leak is found establish if it is gear oil.
6. If so, leak is originating from transfer box.
7. Check two inner (main/transfer) bolts are oil tight, as these holes are tapped into the main transfer case.
8. Remove transfer box to inspect mainshaft collar seal track condition, and front face of transfer case for porosity.
9. If these areas require servicing, transfer gearbox input seal must also be renewed.

CAUTION: Avoid damaging new seal lip and ensure seal is installed flush with machined face. Also ensure new seal is not damaged when reinstallation transfer gearbox.

10. If red A.T.F. type oil is seen leaking during workshop test, investigate main gearbox for cause of leak.

DETENT PLUG OR ELECTRICAL SWITCH LEAKS
Detent plugs and electrical switches do not usually leak. But, it must be noted that they install into open tapped holes in the transfer case and therefore should be considered when looking for source of leak.