ISM, ISMe, and QSM11 – 001-039   Idler Gear, Hydraulic Pump

CAUTION  The grooved side of the rear thrust bearing must be facing toward the gear to prevent damage to the gear and engine during engine operation.

SAE ‘A’ and SAE ‘B’ Install

Use Lubriplate™ 105, or equivalent, to lubricate the thrust bearings and idler gear.

Install the idler gear shaft (8) and rear thrust bearing (7).

NOTE: When an SAE B drive is used, a special hydraulic drive idler shaft with two oil holes is used. With the engine in the upright position, orientate the shaft so that one oil hole is at twelve- o’clock and the other at four-o’clock.

CAUTION  The grooved side of the front thrust bearing must be facing toward the gear to prevent damage to the gear and engine during engine operation.

Install the idler gear (6) and front thrust bearing (5).

NOTE: On SAE “B” drives, install a new rectangular seal on the rear surface of the gear retainer (4) before installing the retainer.

Install the gear retainer (4).

Install the three retaining capscrews and tighten.

SAE ‘B-B’ Install

NOTE: Use shim(s) as necessary for proper idler gear end clearance.

Use Lubriplate™ 105, or equivalent to lubricate the roller bearings and gear.

To install SAE B-B hydraulic drive idler gear assembly, install

• Mounting Spacer (1)
• Tapered Roller Bearing (2)
• Gear Drive (3)
• Tapered Roller Bearing (4)
• Shim (s) (5)
• Idler Gear Shaft (6)
• Mounting Spacer (7)
• Rectangular Seal (8).

The following idler gear end clearance and backlash checks apply to all three idler gears. The same MINIMUM and MAXIMUM values apply, also.

Use a dial indicator gauge with a magnetic base to measure the idler gear end clearance.

Place the contact tip of the gauge against the face of the idler gear.

Idler Gear End Clearance

Use a dial indicator gauge with a magnetic base to measure the idler gear backlash.

Place the contact tip of the gauge against a tooth on the idler gear.

Do not allow the mating gears to move while measuring the backlash.

Idler Gear Backlash