It is essential that both Counter Shaft assemblies of the front and auxiliary sections are timed. This ensures proper tooth contact is made between Main Shaft gears seeking to center on the Main Shaft during torque transfer and mating Counter Shaft gears that distribute the load evenly. If not properly timed, serious damage to the transmission is likely to result from unequal tooth contact, causing the Main Shaft gears to climb out of equilibrium.

Timing is a simple procedure of marking the appropriate teeth of a gear set prior to installation and placing them in proper mesh while in the transmission. In the front section, it is necessary to time only the drive gear set. Depending on the model, only the low range, deep reduction or splitter gear set is timed in the auxiliary section.

Front Section

• Clearly mark the tooth located directly over the drive gear keyway as shown prior to placing each Counter Shaft assembly into the case, This tooth is stamped with an “O” to aid identification.
• Mark any two adjacent teeth on the Main Drive Gear.
• Mark the two adjacent teeth located directly opposite the first set marked on the Main Drive Gear. There should be an equal number of unmarked gear teeth on each side between the marked sets.
• After placing the Main Shaft assembly into the case, the Counter Shaft Bearings are installed to complete installation of the Counter Shaft assemblies. This meshes marked Counter Shaft drive gear teeth with marked Main Drive Gear teeth.

When installing the bearings on the left Counter Shaft, mesh the Counter Shaft drive gear marked tooth with either set of Main Drive Gear two marked teeth.

Repeat the procedure when installing the bearings on the right Counter Shaft; make use of the remaining set of Main Drive Gear two marked teeth to time the assembly.

Auxiliary Section Timing

• Mark any tooth on the low-range gear. Then mark the tooth located 180° from the first marked tooth.
• Mark the valley between the two gear teeth of each Auxiliary Counter Shaft assembly low-range gear stamped with “O” prior to placing each Auxiliary Counter Shaft assembly into the housing.
• Repeat the procedure on each Auxiliary Counter Shaft Reduction Gear.
• To time the Auxiliary Counter Shafts, find the “O” at the rear bearing and place a straight edge from the “O” up to the front and mark the gear tooth. See Service Bulletin TMIB0150 for further timing instructions.

  Note: Timing mark may be under bearing and washer.

Two Marked Teeth 180 Degrees Apart

Auxiliary Counter Shaft Marked