Idler Gear – Remove and Install


Removal Procedure

Standard Idler Gear

Remove:
- the fuel injection pump gear.
- the valve mechanism cover.  Care must be taken in order to ensure that the fuel injection pump timing is not lost during the removal of the fuel pump gear. Carefully follow the procedure in order to remove the fuel pump gear.

Alignment of timing marks

Ensure that Tooling is installed into hole (X) in the camshaft gear. Use Tooling in order to lock the camshaft in the correct position. Ensure that the gears are marked in order to show alignment. Refer to Illustration.


Ensure that Tooling is installed in hole (Y) in the cylinder block. Use Tooling in order to lock the crankshaft in the correct position.


Loosen the nuts (5) on all rocker arms (6). Unscrew the adjusters (4) on all rocker arms (6) until all valves are fully closed. Failure to ensure that all adjusters are fully unscrewed can result in contact between the valves and pistons. Mark the plate (3) in order to show orientation. Identification will ensure that the plate can be installed in the original orientation.
Remove:
- the three setscrews (1).
- the plate (3).


- the assembly of the idler gear (2) and the hub (7) from the recess in the front housing. The idler gear must be tilted during removal.
- the hub (7) from the idler gear (2).

Heavy-Duty Idler Gear

Remove:
- the fuel injection pump gear.
- the valve mechanism cover.
The assembly of heavy-duty idler gear is not serviceable. Do not disassemble the heavy-duty idler gear.

Alignment of timing marks

Ensure that Tooling is installed into hole (X) in the camshaft gear. Use Tooling in order to lock the camshaft in the correct position. Ensure that the gears are marked in order to show alignment. Refer to Illustration.


Ensure that Tooling is installed in hole (Y) in the cylinder block. Use Tooling in order to lock the crankshaft in the correct position.


Loosen the nuts (4) on all rocker arms (5). Unscrew the adjusters (3) on all rocker arms (5) until all valves are fully closed. Failure to ensure that ALL adjusters are fully unscrewed can result in contact between the valves and pistons. Remove the three setscrews (1) from the assembly of heavy-duty idler gear (2).


Remove the assembly of the idler gear (2) from the recess in the front housing. The idler gear must be tilted during removal.

Installation Procedure

Standard Idler Gear

Ensure that number one piston is at top dead center on the compression stroke.


Ensure that Tooling is installed into the hole (X) in the camshaft gear (1).


Ensure that Tooling is installed in hole (Y) in the cylinder block. Use Tooling in order to lock the crankshaft in the correct position.


Clean the idler gear (2) and inspect the idler gear for wear or damage.  If necessary, replace the idler gear. Clean the hub (7) and inspect the hub for wear or damage. If necessary, replace the hub. Lubricate the hub (7) with clean engine oil. Slide the hub (7) into the idler gear (2). Ensure that the timing marks are toward the front of the idler gear.


Align the timing mark on the idler gear (2) with the timing mark on the camshaft gear. Refer to the illustration. Install the assembly of the idler gear (2) and the hub (7) into the recess in the timing case. Ensure that the oil hole (Z) is to the top of the hub. The idler gear must be tilted during installation. Ensure that the holes in the hub are aligned with the holes in the cylinder block. Clean the plate (3) and inspect the plate for wear or damage. If necessary, replace the plate.
Lubricate the plate (3) with clean engine oil. Align the holes in the plate (3) with the holes in the hub (7). Install the plate in the original orientation.
Install the setscrews (1). Remove Tooling. Install the plug (8) to the cylinder block. See the Illustration. Tighten the setscrews (1) to a torque of 44 N·m (32 lb ft).


Checking end play by using a set of feeler gauge’s. Use a set of feeler gauge’s in order to check the end play for the idler gear.

Checking backlash

Check the backlash between the idler gear and the camshaft gear.
Check the backlash between the idler gear and the crankshaft gear.
Lightly lubricate all of the gears with clean engine oil.
Install the fuel injection pump gear.

Heavy-Duty Idler Gear

Ensure that number one piston is at top dead center on the compression stroke.


Ensure that Tooling is installed into the hole (X) in the camshaft gear.


Ensure that Tooling is installed in hole (Y) in the cylinder block. Use Tooling in order to lock the crankshaft in the correct position. Clean the assembly of the idler gear (2) and inspect the assembly of the idler gear for wear or damage. If necessary, replace the assembly of the idler gear. Lubricate the bearings in the assembly of the idler gear (2) with clean engine oil.


Align the timing mark on the idler gear (2) with the timing mark on the camshaft gear. See the illustration. Install the assembly of the idler gear (2) into the recess in the timing case. Ensure that the identification mark TOP is upward. The idler gear must be tilted during installation. Ensure that the holes in assembly of the idler gear are aligned with the holes in the cylinder block. Install the setscrews (1). Remove Tooling. Install the plug (6) to the cylinder block. See Illustration. Tighten the setscrews (1) to a torque of 44 N·m (32 lb ft).


Use Tooling in order to check the end play for the heavy-duty idler gear.
Check the backlash between the idler gear and the camshaft gear.
Check the backlash between the idler gear and the crankshaft gear.
Lightly lubricate all of the gears with clean engine oil.
Install the fuel injection pump gear.