ELBOW AS 3779623 - Caterpillar

Caterpillar: Confidential Yellow
THE DRIVE SHAFT YOKES ON THE REAR AXLES MAY FAIL ON CERTAIN 950F WHEEL LOADERS - COSA LETTER NO. 4 - PI3560 - MAILED COSA
  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.
JULY 31, 1991 COSA LETTER NO. 4 THE DRIVE SHAFT YOKES ON THE REAR AXLES MAY FAIL ON CERTAIN 950F WHEEL LOADERS 3253 PI3560 COMPLETION DATE Termination Date
January 31, 1992 January 31, 1992
Problem
The 9C4090 Yoke may fail on certain 950F Wheel Loaders due to possible incorrect heat treat of the splines.
Affected Product
Model Identification Number 950F 6YG 1 to 885 (exception 6YG483, 828, 846, 847, 858, 862, 865, 867, 868, 870, 873, 874, 877, 878, 880, 882, 883 and 884 already reworked in plant). 6LJ 1 to 40 5PJ 1 to 12
Parts Needed
The following parts will be needed: 2 - 6C7406 Yokes. New part with increased spline length. NOTE : Machines that have been repaired with 9C4090 Yokes shipped from Grimbergen or Leicester after June 21, 1991 do not have to be replaced again. HEBE1392 - 2 -
Action Required
Remove the front and rear axle yokes as per Service Manual. Inspect yoke splines for wear and according to condition rework as follows: Rework I If splines are completely stripped then the axle will need to be removed, disassembled and cleaned for metal contamination. Inspect the pinion splines for damage and replace if necessary. Labor allowance