Synchronizer Assembly Fastener Change
Mack implemented a revised fastener (Part No. 551KC216) into production effective November 28, 2007, on the synchronizer assembly used on its T200 and T300 transmissions, as shown in Figure 1. This revised fastener incorporates Scotch-Grip adhesive, replacing the patch-lock type fastener which was used previously.
If you disassemble the synchronizer assembly, use the revised fastener at reassembly. Tightening torque specification remains the same.
These fasteners are one-time use fasteners. They must be replaced anytime the synchronizer assembly is disassembled.
Changes to Helical Thrust Washer
Dana has made design changes to the helical gear thrust washer and wheel differential cases on the following models: DS/RS344, 404, 405, DSP/RSP41, DST40, DST41, DSH40/RSH40, DSH44/RSH44, 17/19/21/22060S and 22060SH.
These new design features enhance the overall performance of each segment of the axle the parts are located in (power divider section and wheel differential section). The change was implemented in production units starting in mid-2007.
The original design parts and new design parts are 100 percent interchangeable. All kits sold through service containing the original parts will move to the new design parts as individual inventories are depleted.
The helical gear thrust washer change took place August 20, 2007. The 128702 thrust washer, located in the power divider section of forward carriers, is replaced by washer Part No. 132439. The new washer is common in design to the washer featured in the company’s 46K models. It is easily identifiable by the increased surface dimension and the change in the design of the lubrication groove.
The wheel differential case change occurred August 20, 2007. The new wheel differential cases are designed to enhance the lube flow to the wheel differential section. Referred to as the “coreless” design, the new differential cases are designed with new lube passage openings that increase the flow of axle lubricant in and out of the wheel differential nest.
Primary Fuel Filter Revision
The primary fuel filter (Part No. 20863191) used on Mack MP7 and MP8 engines was superseded by a new-style filter (Part No. 21017305), effective October 22, 2007. The revised primary fuel filter can be identified easily by the stepped-down diameter at the bottom of the filter, while the previous filter has straight sides, as shown in Figure 2.
With this revision, there is no change to the fuel filter mounting adapter, as it
will accept either filter. The previous filter (Part No. 20863191) requires an adapter (Part No. 20745607) to attach the fuel/water separator bowl to the bottom of the filter, shown in Figure 3. The new filter (Part No. 21017305) allows the fuel/water separator bowl to attach directly to the filter with no adapter required.
When replacing the previous straight-sided filter with the new stepped-down version, the adapter is not used. Do not discard the adapter as it can be used if inventory of the previous filter is still available.
New Mounting For Temperature Sensor
A new stud and clip are now used on Caterpillar C7 (S/N: C7S1-Up) engines for Blue Bird buses and General Motors configurations. The new stud and clip retain the wiring of the temperature sensors in order to prevent heat from damaging the wiring.
The new 104-6385 stud and the 285-6395 clip are effective on S/N: C7S5265-Up. The new 104-6385 stud and the 285-6395 clip are adaptable back to the first production of the listed engines.
Use the following procedure to mount the sensor:
- Mount the 104-6385 stud and the 285-6395 clip with the following hardware: 6T-5600 boss, 5P-7970 nut, 9M-1974 hard washer, 290-1993 cable strap and 926-1406 temperature sensor.
- Rotate the 926-1406 temperature sensor downward to angles A and B in order to prevent the sensor wiring from fouling the Caterpillar regeneration system housing, as shown in Figures 4 and 5.
Safety Recalls
The National Highway Traffic Safety Administration (NHTSA) has issued the following recalls:
- The diesel particulate filter attachment bracket on 235 Caterpillar C13 and C15 engines may fail allowing the DPF to separate from the chassis and become a road hazard. The engines involved are the 13L and 15L 335 to 625 horsepower turbocharged and air-to-air aftercooled engines.
A crack in this plug can result in a high-pressure fuel spray or leak, which in the presence of an ignition source could result in a fire.
