y, refuse, transit, intercity coaches, or transmissions equipped with an output retarder. Such vocational transmissions can operate at higher temperatures, and for every 18Ëš F increase in fluid temperature, the rate of fluid oxidation is doubled.
Graddy suggests the following three methods to determine when the transmission fluid and filters must be changed:
1) Customers may elect to use the company’s recommended fluid/filter change intervals (allisontransmission.com—Service: Fluid/Filter Change Intervals or Service Tip #1099).
2) A unique Allison feature called Prognostics monitors various operating parameters and alerts the operator when the transmission fluid and filters must be changed.
3) Fluid analysis is employed when a customer desires to use the fluid beyond the recommended change interval or Prognostics alert point. Fluid oxidation limits/fluid analysis is available at the same location of Service Tip #1099.
Graddy itemized a few other items to monitor and manage—aside from changing transmission fluid/filters when required and simple routine inspections—including: determine the frequency of periodic inspection for fluid leaks, loose bolts, clogged breather, damaged or loose hoses, damaged or loose electrical wiring or connectors, worn driveline components, damaged drive axle suspension components and correct suspension ride height for vehicles equipped with air suspension. Allison engineers note that if ambient temperature is below -13˚ F, the transmission should be operated in neutral at idle speed for at least 20 minutes before range selection is attempted.
What about total fluid life cycle cost? If a customer expects the transmission to operate approximately 18,000 hours before the first overhaul, 36 fluid changes would be required. A typical fluid refill quantity is 39 quarts for a 4000 series transmission in a refuse truck. Typical fleet price for TES389 fluid is $3 per quart. Fluid cost alone before the first overhaul would be $4,212 (excluding labor and disposal costs).
A TES295 fluid in this same vocation has a recommended fluid change interval of every 6000 hours. A TES295 fluid is approximately $9 per quart. Fluid cost alone before the first overhaul with TES295 fluid would be $1,053—a savings of more than $3,000.
Allison technical assistance is available by calling 800-252-5283. Fleet managers may obtain a free Operator’s Manual and Mechanic’s Tips at www.allisontransmission.com.