CYLINDER AS 1917734 - Caterpillar

Caterpillar: Confidential Yellow
OPTIONAL OIL TRANSFER FROM TRANSMISSION TO ENGINE 621B,623B, 824C, 825C, 826C PI7095 MAILED WORLDWIDE EXCEPT BRAZIL AND AME RICAS
  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.
OIL TRANSFER FROM TRANSMISSION TO ENGINE, 621B, 623B, 824C Tractors; 825C, 826C Compactors, 1161, 1300, 3150, PI7095 U-21 AU-18 C-17 E-16 O-15 optional Problem On the above models with the listed serial numbers, oil can transfer from the transmission to the engine. This is caused by the spiral grooves in the crankshaft rear seal lip (2W1734 Seal Group). These grooves are intended to direct engine oil back into the crankcase. However, on these models transmission oil can contact the outside of the lip and be transferred to the crankcase. The silicon lip seal formerly used at this location is again used in place of the spiral grooved seal. A spiral grooved seal continues to be used at the front. Affected Serial Numbers And Parts 621B 45P3621-45P3623, 3628, 3629, 3631-3634, 3636, 3639-3641, 3643-3658, 3660, 3662-3683, 3685, 3688-3694 623B 46P2015-46P2018, 2020, 2022-2030, 2032-2061, 2063-2065, 2068, 2072, 2074-2080, 2082-2085 824C 85X1069-85X1078, 1080-1084, 1088-1092, 1094, 1102-1104, 1107, 1111, 1115, 1120, 1121, 1123, 1124, 1128 825C 86X683, 685, 688, 690, 693-697, 721 826C 87X422-87X455, 461, 463, 467, 470, 471, 475, 478-480, 483, 484, 487, 489 Parts Needed: 1-5S9022 Seal 1-4N848 Sleeve Action Requested Inventory Machines. Replace the crankshaft rear seal with the new parts. Remove all the parts in the 2W1734 Seal Group. Use Special Instruction SMHS7100 to install the new parts. Users' Machines. The new parts can be installed before an oil transfer problem. Use the Special Instructions to install the new parts. (SEE ILLUSTRATION) Parts Disposition Dispose of the parts in accordance with your Warranty Bulletin on warranty parts disposition. Termination Date March 31, 1986.