SFN-20240122D Replace rubber isolators

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TICO Document #: SFN-20240122D (formerly TES 121)

Description of Procedure: The new metal spring design reduces the bending moment on the engine flywheel housing and provides sufficient travel in both the upward and downward directions under dynamic loads. The existing rubber isolators do not allow for sufficient travel under dynamic loading. Additionally, adding a rear transmission support reduces the overall weight on the engine flywheel housing and transmission mounting under static loads.

Units Affected: These units were produced between December 2008 and November 2011. The engines that were installed @ 0° inclination have the bracket installed pointing rearward as viewed from the rear of the transmission (Fig 1). The engines installed @ a 2° inclination have the bracket installed with the foot of the bracket pointing forward as viewed from the rear of the transmission (Fig 2).

Parts Required: 71601 Field Kit – 0° Inclination Angle (RS30-380 axle only) OR 71600 Field Kit – 2° Inclination Angle (All axles except RS30-380)

Planned Labor: N/A

Instructions:

71601 Field Kit – 0° Inclination Angle (RS30-380 axle only)

  1. Park vehicle on flat surface, apply parking brake, and chock wheels. If your company utilizes a “Lock Out, Tag Out” policy, you should employ it during this procedure.

  2. Remove all of the parts that are connected at the rear of the engine cradle and the rear of the transmission. Start by ensuring the rear support bracket that is attached to the transmission shows no distress, or replace with a new bracket if required. There are four M12 x 1.75 bolts attaching this bracket to the transmission. These bolts maybe re-used to install a new bracket. Torque these bolts to 66-81 lb-ft. Bracket P/N 12374 is installed with the flange of the bracket facing toward the rear of the vehicle (Fig 1).

  1. Use kit 71601: Install the original mount plate 61641-3, along with mount plate 12371 and mount plate 12371-1 to the rear of the engine cradle as shown in (Fig 1) using two 5/8-11NC x 3 1/2” lg bolts, washers and nylock nuts. . Mounting plate 12371 is installed on the underneath side of the cradle. Install spacer plate 12371-1 and plate 12373 to 61641-3 using two 5/8-11NC x 3” lg bolts, washers and nylock nuts (Fig 1).

  • There should be a gap of approximately ½” between the transmission support and the engine cradle mount.

  1. Install the two springs underneath the transmission support using the 5/8- 11NC x 6 1/2” lg bolts, washers and nylock nuts. Use the heavy washers 60113 on top of the extension plate. Tighten the nut until the spring is just contacting the support bar. Measure and record the height of the bolt that is protruding above the mounting plate. Tighten the nut until you have increased the height of the bolt above the mounting plate an additional 1/8” from its original height (Fig 1). This will provide the proper preload on the springs .

Instructions:

71600 Field Kit – 2° Inclination Angle (All axles except RS30-380)

  1. Remove all of the parts that are connected at the rear of the engine cradle and the rear of the transmission. Start by ensuring the rear support bracket that is attached to the transmission shows no distress, or replace with a new bracket if required. There are four M12 x 1.75 bolts attaching this bracket to the transmission. These bolts maybe re-used to install the new bracket. Torque these bolts to 66-81 lb-ft. Bracket P/N 12048 is installed with the flange of the bracket facing rearward toward the rear of the vehicle (Fig 2).

  1. Use kit 71600: Install the original mount plate 61641-3, along with mount plate 12371 and mount plate 12370 to the rear of the engine cradle as shown in (Fig 1), using two 5/8-11NC x 3 3/4” lg bolts, washers and nylock nuts. Mounting plate 12371 is installed on the underneath side of the cradle.

    There should be a gap of approximately 1” between the transmission support and the engine cradle mount.

  1. Install the two springs underneath the transmission support using the 5/8-11NC x 6 1/2” lg bolts, washers and nylock nuts. Use the heavy washers 60113 on top of the extension plate. Tighten the nut until the spring is just contacting the support bar. Measure and record the height of the bolt that is protruding above the mounting plate. Tighten the nut until you have increased the height of the bolt above the mounting plate an additional 1/8” from its original height (Fig 1). This will provide the proper preload on the springs.

  1. Remove “Lock Out, Tag Out” plaque.

  1. Return vehicle to service.