CHASSIS AR 8W1954 - Caterpillar

The information supplied in this service letter may not be valid after the termination date of this program. Do not perform the work outlined in this Service Letter after the termination date without first contacting your Caterpillar product analyst.
This Program can be administered either before or after a failure. In either case the decision whether to apply the Program is made by the dealer. When reporting the repair, use "PS8485" as the Part Number and "7755" as the Group Number. If administered before failure, use "56" as the Warranty Claim Description Code and use "T" as the SIMS Description Code. If administered after failure, use "96" as the Warranty Claim Description Code and use "Z" as the SIMS Description Code.
Termination Date
December 31, 1996Problem
The 3E6450 Pressure Switch in the steer circuit is failing due to leakage on certain 438B AWS Backhoe Loaders. This problem is caused by the switch being applied in a circuit that sees pressure spikes in excess of its 3000 PSI rating. A new switch is being applied to a portion of the circuit that will see lower pressure spikes.
Affected Product
Model & Identification Number
438B (3KK628, 3KK630, 3KK711, 3KK804, 3KK823, 3KK831, 3KK850, 3KK853, 3KK856, 3KK859, 3KK862, 3KK865, 3KK868, 3KK871, 3KK874, 3KK877, 3KK880, 3KK883, 3KK886, 3KK889, 3KK892, 3KK893, 3KK896, 3KK901, 3KK903, 3KK906, 3KK910, 3KK913, 3KK916, 3KK919, 3KK923, 3KK925, 3KK929, 3KK931, 3KK935, 3KK937, 3KK941, 3KK943, 3KK945, 3KK947, 3KK951, 3KK956, 3KK960, 3KK961, 3KK965, 3KK968, 3KK969, 3KK972, 3KK975, 3KK978, 3KK981, 3KK984, 3KK986, 3KK988, 3KK991, 3KK993, 3KK996, 3KK998, 3KK1002, 3KK1021, 3KK1029, 3KK1030, 3KK1032, 3KK1034, 3KK1036, 3KK1038, 3KK1040, 3KK1041, 3KK1043, 3KK1046, 3KK1047, 3KK1050, 3KK1054-1062, 3KK1068, 3KK1069, 3KK1075, 3KK1078, 3KK1081, 3KK1083-1088, 3KK1091, 3KK1093, 3KK1096, 3KK1099, 3KK1102, 3KK1103, 3KK1108, 3KK1109, 3KK1111, 3KK1115, 3KK1118, 3KK1131, 3KK1134, 3KK1135, 3KK1137, 3KK1140, 3KK1142-1146, 3KK1148, 3KK1150, 3KK1152, 3KK1154, 3KK1156, 3KK1158, 3KK1161-1163, 3KK1165, 3KK1166, 3KK1169, 3KK1172, 3KK1173, 3KK1177, 3KK1180, 3KK1182, 3KK1184, 3KK1186, 3KK1188, 3KK1190, 3KK1192, 3KK1194, 3KK1195, 3KK1198, 3KK1200, 3KK1201, 3KK1203-1209, 3KK1212, 3KK1214, 3KK1216, 3KK1218, 3KK1219, 3KK1221-1224, 3KK1226, 3KK1227, 3KK1229-1231, 3KK1238, 3KK1243, 3KK1245, 3KK1248, 3KK1249, 3KK1252, 3KK1254, 3KK1256, 3KK1258, 3KK1260, 3KK1263-1269, 3KK1271, 3KK1273, 3KK1275, 3KK1277, 3KK1284, 3KK1287, 3KK1291, 3KK1295, 3KK1304, 3KK1305, 3KK1307, 3KK1309, 3KK1312-1314, 3KK1317, 3KK1326, 3KK1332, 3KK1339, 3KK1341, 3KK1342, 3KK1345-1348, 3KK1350-1352, 3KK1355, 3KK1356, 3KK1359, 3KK1360, 3KK1363, 3KK1364, 3KK1367, 3KK1370, 3KK1376, 3KK1377, 3KK1383, 3KK1384, 3KK1386, 3KK1388, 3KK1389, 3KK1391, 3KK1396, 3KK1397, 3KK1400, 3KK1407, 3KK1409, 3KK1410, 3KK1412, 3KK1414, 3KK1415, 3KK1417, 3KK1418, 3KK1421, 3KK1422, 3KK1428-1432, 3KK1434, 3KK1436-1438, 3KK1440, 3KK1446, 3KK1447, 3KK1449, 3KK1450, 3KK1456, 3KK1457, 3KK1460, 3KK1461, 3KK1465, 3KK1466, 3KK1470, 3KK1471, 3KK1475-1477, 3KK1480-1483, 3KK1487, 3KK1491, 3KK1492, 3KK1496, 3KK1497, 3KK1501, 3KK1502, 3KK1513, 3KK1514, 3KK1533, 3KK1541, 3KK1552, 3KK1553, 3KK1557-1561, 3KK1569, 3KK1570, 3KK1575, 3KK1576, 3KK1581-1583, 3KK1586, 3KK1587, 3KK1589, 3KK1590, 3KK1593, 3KK1596, 3KK1603, 3KK1604, 3KK1612-1614, 3KK1619, 3KK1620, 3KK1633, 3KK1634, 3KK1642, 3KK1643, 3KK1645, 3KK1651, 3KK1652, 3KK1656, 3KK1659, 3KK1660, 3KK1679, 3KK1685, 3KK1686, 3KK1689, 3KK1710, 3KK1711-1714, 3KK1716, 3KK1723, 3KK1727, 3KK1728, 3KK1731, 3KK1732, 3KK1736, 3KK1747, 3KK1753, 3KK1757, 3KK1761, 3KK1765, 3KK1771, 3KK1772, 3KK1778, 3KK1780, 3KK1785, 3KK1788, 3KK1792, 3KK1793, 3KK1796, 3KK1797, 3KK1802, 3KK1814, 3KK1819, 3KK1820, 3KK1828, 3KK1846, 3KK1850, 3KK1853, 3KK1856, 3KK1858-1861, 3KK1864, 3KK1865, 3KK1867, 3KK1868, 3KK1872, 3KK1873, 3KK1876, 3KK1877, 3KK1879, 3KK1880, 3KK1883, 3KK1884, 3KK1886, 3KK1887, 3KK1892, 3KK1893, 3KK1897, 3KK1898, 3KK3084, 3KK3087, 3KK3089-3091, 3KK3094, 3KK3095,