THE DRIVE SHAFT YOKES ON THE REAR AXLES MAY FAIL ON CERTAIN 950F WHEEL LOADERS - COSA LETTER NO. 4 - PI3560 - MAILED COSA Caterpillar

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   

January 31, 1992  January 31, 1992

The 9C4090 Yoke may fail on certain 950F Wheel Loaders due to possible
incorrect heat treat of the splines.

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

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 -

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 16
hours per axle includes yoke replacement on both axles.
Rework II
If splines are worn but still engage the pinion splines, then only the
respective axle oil will need changing. Labor allowance 3 hours to
replace both front and rear yokes, topping and or changing axle oil as
necessary. This labor allowance also applies to straight yoke
replacement on no failure and stock machines.
Rework III
If an earlier rear yoke failure was repaired with a 9C4090 Yoke
shipped from Grimbergen or Leicester after June 21, 1991, then only
the front yoke will need replacing. Suggest that the rear 9C4090 Yoke
is switched to the front axle and that the new 6C7406 Yoke is mounted
on the rear axle. Labor allowance 3 hours.
NOTE : The new yoke is not fitted with a guard. Remove the 7V3791
Guards from the old yokes and install on the new yokes.
Any additional parts should be claimed separately in accordance with
the warranty procedures.
SERVICE CLAIMS ALLOWANCES
AVSpare Dlr Suggested Customer Suggested
--------------- ---------------- ------------------
Parts Lab. Hrs. Parts Lab. Hrs. Parts Lab. Hrs.
(D/N) (Sell)  (C/L) (Sell)
Rework I 100% 16 0 0 0 0
Rework II 100% 3 0 0 0 0
Rework III 100% 3 0 0 0 0

Retain parts until claim settlement has been made.
- 3 -
PARTS STOCK
Remove any 9C4090 Yokes in the parts department that were shipped from
Grimbergen or Leicester before June 21, 1991. Submit a separate claim
making reference to this Service Letter. Yokes from other sources are
not affected.
MAKE EVERY EFFORT TO COMPLETE THIS PROGRAM AS SOON AS POSSIBLE.