c. Fluid Analysis. Transmission protection and fluid change intervals can be optimized by monitoring fluid oxidation according to the tests and limits shown in Table 2–5. Consult your local telephone directory for fluid analysis firms. To make sure of consistent and accurate fluid analysis, use only one fluid analysis firm. Refer to GN2055EN, Technician’s Guide for Automatic Transmission Fluid for additional information. Table 2–5. Fluid Analysis Measurement Limits Test
Limit
Viscosity
±25 percent change from new fluid
Total Acid Number
+3.0* change from new fluid (Ref. SIL 17TR96)
*mg
of potassium hydroxide (KOH) to neutralize a gram of fluid
2–8. TRANSMISSION FLUID CONTAMINATION a. Fluid Examination. At each fluid change, examine the drained fluid for evidence of dirt or water. A normal amount of condensation (not to exceed 0.2 percent) will appear in the fluid during operation. b. Water. Obvious water contamination of the transmission fluid or transmission fluid in the cooler (heat exchanger) water indicates a leak between the water and fluid areas of the cooler. Inspect and pressure test the cooler to confirm the leak. Replace leaking coolers. NOTE: Cooler water can also be contaminated by engine oil; be sure to locate the correct source of cooler water contamination. c. Engine Coolant. CAUTION: Engine coolant in the transmission hydraulic system requires immediate action to prevent malfunction and possible serious transmission damage. Completely disassemble, inspect, and clean the transmission. Remove all traces of the coolant and varnish deposits resulting from engine coolant contamination (ethylene glycol).
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