PRODUCT SUPPORT PROGRAM FOR REWORKING THE DIFFERENTIAL LOCK SYSTEM ON CERTAIN 621H, 621K, 623H AND 623K WHEEL TRACTOR-SCRAPERS Caterpillar

PRODUCT SUPPORT PROGRAM FOR REWORKING THE DIFFERENTIAL LOCK SYSTEM ON CERTAIN 621H, 621K, 623H AND 623K WHEEL TRACTOR-SCRAPERS [UEBE1228]

POWER TRAIN

DIFFERENTIAL & BEVEL GEAR GP

PRODUCT SUPPORT PROGRAM FOR REWORKING THE DIFFERENTIAL LOCK SYSTEM ON CERTAIN 621H, 621K, 623H AND 623K WHEEL TRACTOR-SCRAPERS

UEBE1228-00

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07Oct2020

U-596

A-491

D-562

O-551

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After Failure Only	PRODUCT SUPPORT PROGRAM FOR REWORKING THE DIFFERENTIAL LOCK SYSTEM ON CERTAIN 621H, 621K, 623H AND 623K WHEEL TRACTOR-SCRAPERS
3264 3272		PS54450

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NOTE:	AVSpare’s obligations under this Service Letter are subject to, and shall not apply in contravention of, the laws, rules, regulations, directives, ordinances, orders, or statutes of the United States, or of any other applicable jurisdiction, without recourse or liability with respect to AVSpare.
NOTE:	This Program can only be administered after a failure occurs. The decision whether to apply the Program is made by the dealer. When reporting the repair, use "PS54450" as the Part Number and "7755" as the Group Number. Use "96" as the Warranty Claim Description Code and use "Z" as the SIMS Description Code.

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NOTE:

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 AVSpare product analyst.

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TERMINATION DATE

31Oct2022

PROBLEM

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The differential locks are failing at low hours on certain 621H, 621K, 623H, and 623K Wheel Tractor-Scrapers. Debris generated during clutch engagement can be trapped inside the piston and damage the piston and seals causing the hydraulic oil to mix with the differential oil.

AFFECTED PRODUCT

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Model	Identification Number
*****Group 1*****
621H	DBK00102, 106, 108-109, 116, 119
623H	DBF00127-00128, 130-131, 136, 140, 142, 147, 152-153, 161, 168-169, 172, 175

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*****Group 2*****
621H	DBK00101, 103-105, 107, 110-115, 117-118, 120-131 EAZ00101-00125
621H OEM	HKK00101-00139 NYY00101-00129
623H	DBF00102-00126, 129, 132-135, 137-139, 141, 143-146, 148-151, 154-160, 162-167, 170-171, 173-174 EJD00101-00105

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*****Group 3*****
621K	WTA00101-00102, 104, 107-108, 111, 113 WTL00101
621K OEM	WTE00103-00104
623K	WTB00102-00103, 105, 107, 109, 111-112, 114, 118, 124, 128, 130, 133-134, 140, 145, 147, 150, 152, 154, 157, 162-163, 170, 173, 177, 179, 181, 183, 185, 188-189, 191, 195-196, 201, 206, 209-211 WTM00104, 107-108

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*****Group 4*****
621K	WTA00103, 105-106, 109-110, 112, 114-118
621K OEM	WTE00101-00102, 105-121 WTP00101-00112
623K	WTB00101, 104, 106, 108, 110, 113, 115-117, 119-123, 125-127, 129, 131-132, 135-139, 141-144, 146, 148-149, 151, 153, 155-156, 158-161, 164-169, 171-172, 174-176, 178, 180, 182, 184, 186-187, 190, 192-194, 197-200, 202-205, 207-208, 212-216 WTM00101-00103, 105-106, 109-110

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*****Group 5*****
621K	WTA00119-00123, 126-127, 130-138, 141-142, 144-160 WTL00102-00103
621K OEM	WTE00122-00163 WTP00113-00119
623K	WTB00217-00227, 230-240, 243-253, 255-257, 260-266, 268, 272-276, 278, 282-293, 297, 299-300, 303-306, 308, 313-315, 319-321, 324-325, 328-334, 337, 340, 342, 345-351, 355-356, 358-360, 363-364, 366, 371-388, 391-396, 399, 401-406 WTM00111-00113

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*****Group 6*****
621K	WTA00124-00125, 128-129, 139-140, 143 WTL00104-00106
623K	WTB00228-00229, 241-242, 254, 258-259, 267, 269-271, 277, 279-281, 294-296, 298, 301-302, 307, 309-312, 316-318, 322-323, 326-327, 335-336, 338-339, 341, 343-344, 352-354, 357, 361-362, 365, 367-370, 389-390, 397-398, 400 WTM00114-00124

PARTS NEEDED

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Qty	Part Number	Description
*****Group 1*****
1	1B8736	KEY-WOODRUFF
4	1D4588	BOLT
1	2D8364	SEAL-O-RING
1	2M9780	SEAL-O-RING-STOR
2	3D8422	SEAL-O RING
1	3F3728	RING-SNAP
2	4D1577	SEAL-O RING
2	4F2411	SEAL-O RING
1	5H7370	SEAL-O-RING
1	5P6628	WIRE-LOCK (1 METER)
1	5S3676	SEAL-O RING
1	5T5296	SPACER
2	6D2718	DOWEL
1	6F0711	SEAL-O RING
3	6V9746	SEAL-O-RING-ORFS
12	7D4893	SPRING
1	7D6101	WASHER-THRUST
1	7D6102	WASHER-THRUST
1	7D6319	RING
1	7J9108	SEAL-O-RING-ORFS
1	8D5096	SEAL-O RING
12	8T4121	WASHER-HARD
1	9F7283	SEAL-O-RING
1	9H3360	SEAL-O RING
2	1372429	SEAL GP-DUO CONE
12	1837121	BOLT-HEX HEAD
1	1880632	SEAL-BRAKE
1	1880633	SEAL-BRAKE
2	2287091	SEAL-O-RING-ORFS
2	2287092	SEAL-O-RING-ORFS
2	2287093	SEAL-O-RING-ORFS
2	3193887	SEAL GP
1	4898901	SCREEN AS
1	4940663	HOUSING-SPRING
1	4940664	PISTON
1	5600923	CYLINDER
1	5802319	HOSE AS
1	5836419	JAW-CLUTCH
1	5836420	JAW-CLUTCH
In order to allow equitable parts availability to all participating dealers, please limit your initial parts order to not exceed 1% of dealership population. This is an initial order recommendation only, and the ultimate responsibility for ordering the total number of parts needed to satisfy the program lies with the dealer.
*****Group 2*****
1	1B8736	KEY-WOODRUFF
4	1D4588	BOLT
1	2D8364	SEAL-O-RING
1	2H3926	LOCKWASHER
3	2M9780	SEAL-O-RING-STOR
1	2P1293	LOCKNUT-BULKHEAD
2	3D2824	SEAL-O-RING-STOR
2	3D8422	SEAL-O RING
1	3F3728	RING-SNAP
1	3J1907	SEAL-O-RING-STOR
2	3J5389	PLUG-NPTF
2	3K0360	SEAL-O-RING-STOR
2	4D1577	SEAL-O RING
2	4F2411	SEAL-O RING
1	5H7370	SEAL-O-RING
1	5P6628	WIRE-LOCK (1 METER)
1	5S3676	SEAL-O RING
1	5T5296	SPACER
2	6D2718	DOWEL
1	6F0711	SEAL-O RING
1	6V0409	SEAL-BONDED
1	6V0852	CAP-DUST
1	6V3965	ADAPTER-STR
1	6V8626	ADAPTER-ELBOW
1	6V8642	ADAPTER-STR
11	6V9746	SEAL-O-RING-ORFS
12	7D4893	SPRING
1	7D6101	WASHER-THRUST
1	7D6102	WASHER-THRUST
1	7D6319	RING
3	7J9108	SEAL-O-RING-ORFS
1	7X0872	ADAPTER-TEE
1	8D5096	SEAL-O RING
12	8T4121	WASHER-HARD
1	9F7283	SEAL-O-RING
1	9H3360	SEAL-O RING
2	1372429	SEAL GP-DUO CONE
1	1622896	ADAPTER-STRAIGHT
12	1837121	BOLT-HEX HEAD
1	1880632	SEAL-BRAKE
1	1880633	SEAL-BRAKE
5	2147568	SEAL-O-RING-STOR
1	2240554	FILM-WARNING
1	2287089	SEAL-O-RING-ORFS
1	2287090	SEAL-O-RING-ORFS
2	2287091	SEAL-O-RING-ORFS
2	2287092	SEAL-O-RING-ORFS
3	2287093	SEAL-O-RING-ORFS
1	2385080	SEAL-O-RING-STOR
1	2385084	SEAL-O-RING-STOR
2	3193887	SEAL GP
1	4898901	SCREEN AS
1	4920294	HOSE AS
1	4940663	HOUSING-SPRING
1	4940664	PISTON
1	5048900	MANIFOLD GP-RLF
1	5600923	CYLINDER
1	5802319	HOSE AS
1	5836419	JAW-CLUTCH
1	5836420	JAW-CLUTCH
In order to allow equitable parts availability to all participating dealers, please limit your initial parts order to not exceed 1% of dealership population. This is an initial order recommendation only, and the ultimate responsibility for ordering the total number of parts needed to satisfy the program lies with the dealer.
*****Group 3*****
1	1B8736	KEY-WOODRUFF
4	1D4588	BOLT
1	2D8364	SEAL-O-RING
2	2M9780	SEAL-O-RING-STOR
2	3D8422	SEAL-O RING
1	3F3728	RING-SNAP
2	3P1155	SEAL-O-RING
2	3S2093	STRAP-CABLE
2	4D1577	SEAL-O RING
2	4F2411	SEAL-O RING
1	5H7370	SEAL-O-RING
1	5P6628	WIRE-LOCK (1 METER)
1	5S3676	SEAL-O RING
1	5T5296	SPACER
2	6D2718	DOWEL
1	6F0711	SEAL-O RING
1	6V9746	SEAL-O-RING-ORFS
12	7D4893	SPRING
1	7D6101	WASHER-THRUST
1	7D6102	WASHER-THRUST
1	7D6319	RING
1	7J9108	SEAL-O-RING-ORFS
1	8D5096	SEAL-O RING
12	8T4121	WASHER-HARD
4	8T4224	WASHER-HARD
4	8T4908	BOLT-HEX HEAD
1	9F7283	SEAL-O-RING
1	9H3360	SEAL-O RING
2	1372429	SEAL GP-DUO CONE
12	1837121	BOLT-HEX HEAD
1	1880632	SEAL-BRAKE
1	1880633	SEAL-BRAKE
4	2287090	SEAL-O-RING-ORFS
2	2287092	SEAL-O-RING-ORFS
2	2287093	SEAL-O-RING-ORFS
2	3193887	SEAL GP
2	3747464	CAP-SEAL
1	4898901	SCREEN AS
1	4940663	HOUSING-SPRING
1	4940664	PISTON
1	5600923	CYLINDER
1	5802319	HOSE AS
1	5836419	JAW-CLUTCH
1	5836420	JAW-CLUTCH
2	5994474	COVER
In order to allow equitable parts availability to all participating dealers, please limit your initial parts order to not exceed 1% of dealership population. This is an initial order recommendation only, and the ultimate responsibility for ordering the total number of parts needed to satisfy the program lies with the dealer.
*****Group 4*****
1	1B8736	KEY-WOODRUFF
4	1D4588	BOLT
1	2D8364	SEAL-O-RING
1	2H3926	LOCKWASHER
3	2M9780	SEAL-O-RING-STOR
1	2P1293	LOCKNUT-BULKHEAD
2	3D2824	SEAL-O-RING-STOR
2	3D8422	SEAL-O RING
1	3F3728	RING-SNAP
2	3J1907	SEAL-O-RING-STOR
2	3J5389	PLUG-NPTF
3	3K0360	SEAL-O-RING-STOR
2	3P1155	SEAL-O-RING
2	3S2093	STRAP-CABLE
2	4D1577	SEAL-O RING
2	4F2411	SEAL-O RING
1	5H7370	SEAL-O-RING
1	5K9090	SEAL-O-RING-ORFS
1	5P6628	WIRE-LOCK (1 METER)
1	5S3676	SEAL-O RING
1	5T5296	SPACER
2	6D2718	DOWEL
1	6F0711	SEAL-O RING
1	6V0409	SEAL-BONDED
1	6V0852	CAP-DUST
1	6V3965	ADAPTER-STR
1	6V8397	SEAL-O-RING-ORFS
1	6V8398	SEAL-O-RING-ORFS
1	6V8626	ADAPTER-ELBOW
1	6V8642	ADAPTER-STR
8	6V9746	SEAL-O-RING-ORFS
12	7D4893	SPRING
1	7D6101	WASHER-THRUST
1	7D6102	WASHER-THRUST
1	7D6319	RING
4	7J9108	SEAL-O-RING-ORFS
1	7M8485	SEAL-O-RING-STOR
1	8D5096	SEAL-O RING
12	8T4121	WASHER-HARD
4	8T4224	WASHER-HARD
4	8T4908	BOLT-HEX HEAD
1	9F7283	SEAL-O-RING
1	9H3360	SEAL-O RING
2	1372429	SEAL GP-DUO CONE
1	1622896	ADAPTER-STRAIGHT
12	1837121	BOLT-HEX HEAD
1	1880632	SEAL-BRAKE
1	1880633	SEAL-BRAKE
3	2147568	SEAL-O-RING-STOR
1	2240554	FILM-WARNING
4	2287090	SEAL-O-RING-ORFS
2	2287092	SEAL-O-RING-ORFS
2	2287093	SEAL-O-RING-ORFS
2	3193887	SEAL GP
2	3747464	CAP-SEAL
1	4898901	SCREEN AS
1	4908821	HOSE AS
1	4913781	MANIFOLD GP-RLF
1	4940663	HOUSING-SPRING
1	4940664	PISTON
1	5600923	CYLINDER
1	5802319	HOSE AS
1	5836419	JAW-CLUTCH
1	5836420	JAW-CLUTCH
2	5994474	COVER
In order to allow equitable parts availability to all participating dealers, please limit your initial parts order to not exceed 1% of dealership population. This is an initial order recommendation only, and the ultimate responsibility for ordering the total number of parts needed to satisfy the program lies with the dealer.
*****Group 5*****
1	1B8736	KEY-WOODRUFF
4	1D4588	BOLT
1	2D8364	SEAL-O-RING
2	2M9780	SEAL-O-RING-STOR
2	3D8422	SEAL-O RING
1	3F3728	RING-SNAP
2	3P1155	SEAL-O-RING
2	3S2093	STRAP-CABLE
2	4D1577	SEAL-O RING
2	4F2411	SEAL-O RING
1	5H7370	SEAL-O-RING
1	5P6628	WIRE-LOCK (1 METER)
1	5S3676	SEAL-O RING
1	5T5296	SPACER
2	6D2718	DOWEL
1	6F0711	SEAL-O RING
1	6V9746	SEAL-O-RING-ORFS
12	7D4893	SPRING
1	7D6101	WASHER-THRUST
1	7D6102	WASHER-THRUST
1	7D6319	RING
1	7J9108	SEAL-O-RING-ORFS
1	8D5096	SEAL-O RING
12	8T4121	WASHER-HARD
4	8T4224	WASHER-HARD
4	8T4908	BOLT-HEX HEAD
1	9F7283	SEAL-O-RING
1	9H3360	SEAL-O RING
2	1372429	SEAL GP-DUO CONE
12	1837121	BOLT-HEX HEAD
1	1880632	SEAL-BRAKE
1	1880633	SEAL-BRAKE
4	2287090	SEAL-O-RING-ORFS
2	2287092	SEAL-O-RING-ORFS
2	2287093	SEAL-O-RING-ORFS
2	3193887	SEAL GP
2	3747464	CAP-SEAL
1	4940663	HOUSING-SPRING
1	4940664	PISTON
1	5600923	CYLINDER
1	5802319	HOSE AS
1	5836419	JAW-CLUTCH
1	5836420	JAW-CLUTCH
2	5994474	COVER
In order to allow equitable parts availability to all participating dealers, please limit your initial parts order to not exceed 1% of dealership population. This is an initial order recommendation only, and the ultimate responsibility for ordering the total number of parts needed to satisfy the program lies with the dealer.
*****Group 6*****
1	1B8736	KEY-WOODRUFF
4	1D4588	BOLT
1	2D8364	SEAL-O-RING
2	2M9780	SEAL-O-RING-STOR
2	3D8422	SEAL-O RING
1	3F3728	RING-SNAP
2	3P1155	SEAL-O-RING
2	3S2093	STRAP-CABLE
2	4D1577	SEAL-O RING
2	4F2411	SEAL-O RING
1	5H7370	SEAL-O-RING
1	5P6628	WIRE-LOCK (1 METER)
1	5S3676	SEAL-O RING
1	5T5296	SPACER
2	6D2718	DOWEL
1	6F0711	SEAL-O RING
1	6V9746	SEAL-O-RING-ORFS
12	7D4893	SPRING
1	7D6101	WASHER-THRUST
1	7D6102	WASHER-THRUST
1	7D6319	RING
1	7J9108	SEAL-O-RING-ORFS
1	8D5096	SEAL-O RING
12	8T4121	WASHER-HARD
4	8T4224	WASHER-HARD
4	8T4908	BOLT-HEX HEAD
1	9F7283	SEAL-O-RING
1	9H3360	SEAL-O RING
2	1372429	SEAL GP-DUO CONE
12	1837121	BOLT-HEX HEAD
1	1880632	SEAL-BRAKE
1	1880633	SEAL-BRAKE
4	2287090	SEAL-O-RING-ORFS
2	2287092	SEAL-O-RING-ORFS
2	2287093	SEAL-O-RING-ORFS
2	3193887	SEAL GP
2	3747464	CAP-SEAL
1	4940663	HOUSING-SPRING
1	4940664	PISTON
1	5600923	CYLINDER
1	5802319	HOSE AS
1	5836419	JAW-CLUTCH
1	5836420	JAW-CLUTCH
2	5994474	COVER
In order to allow equitable parts availability to all participating dealers, please limit your initial parts order to not exceed 1% of dealership population. This is an initial order recommendation only, and the ultimate responsibility for ordering the total number of parts needed to satisfy the program lies with the dealer.

ACTION REQUIRED

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For all groups replace the existing four tooth differential lock jaws with updated eight tooth differential lock jaws.

For Groups 2 and 4, update the differential lock system to the new high pressure differential lock system. The installation of high pressure differential lock requires the three updates listed below:

1. A new differential lock mechanism (housing and piston) with a reduced volume.

2. New lines routing that will go from the fan/brake/differential lock manifold through the front of the differential case via a bulkhead and directly to the differential lock mechanism.

3. New fan/brake/differential lock manifold that has increased pressure and flow capability.

Refer to M0075476, Special Instruction, "Procedure to Improve the Differential Lock on Certain 620H and 620K Wheel Tractor-Scrapers", for the procedure to install high pressure differential lock system and the eight tooth differential lock jaws for machines that have not updated to the high pressure differential lock system.

Refer to M0123057, Special Instruction, "Procedure to Update the Differential Lock Jaws on Certain 620H and 620K Wheel Tractor-Scrapers", for the procedure to install the eight tooth differential lock jaws for machines that have already updated to the high pressure differential lock system.

For Group 3, 4, 5, and 6 machines, remove the wheel speed sensor group from the machine. The removal of the wheel speed sensor group will prevent debris generation and will prevent debris from damaging the differential lock piston seals. Removal of the wheel speed sensor group will require new transmission/chassis software.

Software to be installed:
597-9738 Transmission/Chassis Software

Note: Removal of the wheel speed sensor groups will cause the following changes:
- Differential Lock Engagement Protection (DLEP), Tire Spin Reduction (TSR), and Advanced Tire Spin Reduction (ATSR) will be disabled.
- Changing the Advanced Tire Spin Reduction Installation Status configuration in Cat ET to "Installed" will not enable this feature.
- The Tire Spin Reduction button backlight on the keypad will be disabled. LED indicators will be disabled. The Tire Spin Reduction button LED indicator blink only when the Help Feature button is pushed.
- Total Differential Lock Engagement Protection Activation Count does not increment in Cat ET.
- Left Front Wheel Speed, Right Front Wheel Speed, Left Front Axle Speed, and Right Front Axle Speed parameters will show * * * in display.

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SERVICE CLAIM ALLOWANCES

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Product smu/age whichever comes first	AVSpare		Dealer Suggested		Customer Suggested
Product smu/age whichever comes first	Parts %	Labor Hrs%	Parts %	Labor Hrs%	Parts %	Labor Hrs%
*****Group 1*****
0-6000 hrs, 0-132 mo	100.0%	100.0%	0.0%	0.0%	0.0%	0.0%
6001-12000 hrs, 133-144 mo	33.0%	50.0%	0.0%	0.0%	50.0%	50.0%

NOTE: This is a 50.0-hour job for Group 1

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Product smu/age whichever comes first	AVSpare		Dealer Suggested		Customer Suggested
Product smu/age whichever comes first	Parts %	Labor Hrs%	Parts %	Labor Hrs%	Parts %	Labor Hrs%
*****Group 2*****
0-6000 hrs, 0-132 mo	100.0%	100.0%	0.0%	0.0%	0.0%	0.0%
6001-12000 hrs, 133-144 mo	33.0%	50.0%	0.0%	0.0%	50.0%	50.0%

NOTE: This is a 62.0-hour job for Group 2

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Product smu/age whichever comes first	AVSpare		Dealer Suggested		Customer Suggested
Product smu/age whichever comes first	Parts %	Labor Hrs%	Parts %	Labor Hrs%	Parts %	Labor Hrs%
*****Group 3*****
0-6000 hrs, 0-96 mo	100.0%	100.0%	0.0%	0.0%	0.0%	0.0%
6001-12000 hrs, 97-108 mo	33.0%	50.0%	0.0%	0.0%	50.0%	50.0%

NOTE: This is a 52.0-hour job for Group 3

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Product smu/age whichever comes first	AVSpare		Dealer Suggested		Customer Suggested
Product smu/age whichever comes first	Parts %	Labor Hrs%	Parts %	Labor Hrs%	Parts %	Labor Hrs%
*****Group 4*****
0-6000 hrs, 0-96 mo	100.0%	100.0%	0.0%	0.0%	0.0%	0.0%
6001-12000 hrs, 97-108 mo	33.0%	50.0%	0.0%	0.0%	50.0%	50.0%

NOTE: This is a 64.0-hour job for Group 4

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Product smu/age whichever comes first	AVSpare		Dealer Suggested		Customer Suggested
Product smu/age whichever comes first	Parts %	Labor Hrs%	Parts %	Labor Hrs%	Parts %	Labor Hrs%
*****Group 5*****
0-6000 hrs, 0-96 mo	100.0%	100.0%	0.0%	0.0%	0.0%	0.0%
6001-12000 hrs, 97-108 mo	33.0%	50.0%	0.0%	0.0%	50.0%	50.0%

NOTE: This is a 52.0-hour job for Group 5

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Product smu/age whichever comes first	AVSpare		Dealer Suggested		Customer Suggested
Product smu/age whichever comes first	Parts %	Labor Hrs%	Parts %	Labor Hrs%	Parts %	Labor Hrs%
*****Group 6*****
0-6000 hrs, 0-96 mo	100.0%	100.0%	0.0%	0.0%	0.0%	0.0%
6001-12000 hrs, 97-108 mo	33.0%	50.0%	0.0%	0.0%	50.0%	50.0%