Table 2-1.  Unit Level Preventive Maintenance Checks and Services HMMWV (Cont'd) ITEM NO. INTERVAL ITEM TO BE INSPECTED PROCEDURES 30 Annually Electrical Inspect all wiring and wiring harness Broken, frayed, split Wiring for frays, splits, missing insulation, or wires or harness. poor connections. Repair any worn wiring (para. 4-85). If wiring cannot be repaired, notify DS maintenance. 30.1 Annually Engine Observe engine and vehicle operation Vehicle fails to operate Running for rough idle, rough running, lack properly. Test of power, and unusual noise or vibration (para. 2-18). 30.2 Annually Transmission   Perform AOAP sample. 31 Biennially   Transmission TM 9-2320-280-20-1 2-26 Change 1 NOT FULLY MISSION CAPABLE IF: CAUTION Use Dexron® II or Dexron® III for 3L80 transmission. Use only Dexron® III for 4L80-E transmission. Failure to use only Dexron® III for 4L80E transmission will cause damage to transmission. NOTE •  Change fluid every 12,000 miles (19,300 km) or biennially, whichever occurs first (para. 5-2a). Inspect either 3L80 or 4L80-E transmission drainplug for metal particles. •  Replace transmission oil filter each time transmission is drained. Fill 3L80 transmission with 6 quarts (5.7 L) of Dexron® II or Dexron® III. Fill 4L80-E transmission with 7.7 quarts (7.3 L) of only Dexron® III. In arctic conditions, use OEA in both model transmissions. CAUTION Use Dexron® II or Dexron® III for 3L80 transmission. Use only Dexron® III for 4L80-E transmission. Failure to use only Dexron® III for 4L80E transmission will cause damage to transmission. NOTE •  Oil and oil filter will be changed when they are known to be contaminated, clogged, or when service is recommended by AOAP laboratory. •  Replace transmission oil filter each time transmission is drained. Fill 3L80 transmission with 6 quarts (5.7 L) of Dexron® II or Dexron® III. Fill 4L80-E transmission with 7.7 quarts (7.3 L) of only Dexron® III. In arctic conditions, use OEA in both model transmissions.