PRODUCT SUPPORT PROGRAM FOR RELOCATING A CHECK VALVE IN THE AXLE OIL COOLING SYSTEM ON CERTAIN 988G WHEEL LOADERS AND 834G WHEEL DOZERS Caterpillar

PRODUCT SUPPORT PROGRAM FOR RELOCATING A CHECK VALVE IN THE AXLE OIL COOLING SYSTEM ON CERTAIN 988G WHEEL LOADERS AND 834G WHEEL DOZERS

Usage:

SEBE8182

October 10, 2002
U-272
A-186
AU-201
S-200
H-198
O-220

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*before or* *after failure*	PRODUCT SUPPORT PROGRAM FOR RELOCATING A CHECK VALVE IN THE AXLE OIL COOLING SYSTEM ON CERTAIN 988G WHEEL LOADERS AND 834G WHEEL DOZERS
1365 5067		PS41131

NOTE: This Program can be administered either before or after failure. In either case the decision whether to apply the Program is made by the dealer. When reporting the repair, use "PS41131" 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.

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 Caterpillar product analyst.

Termination Date

October 31, 2004

PROBLEM

A check valve may need to be relocated in the axle oil cooling system on certain 988G Wheel Loaders and 834G Wheel Dozers equipped with an axle cooler. The core assembly for the axle oil cooler can fail when the system is operated in severe cold temperatures (below -18 degrees C (0 degrees F)). The increased viscosity of the cold oil can create high pressures in the axle oil cooler system and rupture the rear core assembly. A check valve can be relocated to eliminate this problem.

AFFECTED PRODUCT

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Model	Identification Number
*** Group 1 ***
988G	2TW74-79, 81-87, 89-92, 95, 97, 102, 105, 107, 110, 111, 113, 114, 116, 118, 119, 123, 124, 126, 127, 130-135, 137-142, 144, 149-151, 153, 154, 156, 157, 160-162, 165, 167, 170, 172-174, 176, 177, 179, 181, 302, 304, 307, 311, 313, 319, 321-328, 330, 334, 336, 337, 341-343
834G	6GZ166-168, 212
*** Group 2 ***
988G	2TW346, 353, 358-360, 363-365, 368,369, 371, 372, 376-378, 380-382, 388-390, 392, 399-402, 404, 405, 408-411, 413-417, 419-424, 429, 430, 432, 436, 437, 445, 451, 454, 457, 458, 460, 463, 464, 468, 470, 473, 476, 482, 487, 489, 490, 498, 501, 502, 509, 511-513, 515, 518, 523, 525, 526, 530-532, 534, 535, 537, 539, 543, 547, 550-556, 558, 564-566, 568, 569, 572, 573, 575, 578-582, 584, 590, 594, 595, 597, 600-602, 608, 609, 613, 614, 616, 619-623, 625-627, 634, 636, 638, 642, 646-648, 651, 653, 656, 657 BNH333, 334, 337, 338, 341-344, 346, 347, 353-355, 357, 361, 370, 379-381, 383, 385, 387, 389, 391, 393, 394, 396, 397, 400, 402-410, 415-418, 425, 427, 429, 430, 433, 435-439, 441, 444, 446, 447, 449, 451-453, 455, 456, 458, 461, 463, 465-467, 469, 471, 472, 474, 475, 477, 480, 481, 484, 488, 492, 493, 495, 496, 498, 507, 508, 510, 513, 516-518, 521, 523, 533, 537, 540, 554-556, 558, 559, 561-565, 567, 570, 577, 580, 582, 584, 585, 589, 590
834G	BPC130-132, 137, 138

PARTS NEEDED

***** Group 1 *****

1 - 8C9029 Union
1 - 3D2824 Seal - O-Ring
3 - 7M8485 Seal - O-Ring
1 - 6V5258 Adapter
1 - 6V8716 Connector
1 - 6V8990 Elbow - 45 Degree (for 834G only)
5 - 6V9746 Seal - O-Ring (only four are needed for 988G)
1 - 1234021 Hose Assembly (dealer fabricated)
1 - 1947276 Hose Assembly (dealer fabricated)

***** Group 2 *****

1 - 8C9029 Union
1 - 3D2824 Seal - O-Ring
3 - 7M8485 Seal - O-Ring
1 - 6V5258 Adapter
1 - 6V8716 Connector
1 - 6V8791 Tee
6 - 6V9746 Seal - O-Ring
1 - 2232111 Hose Assembly (for 988G only - dealer fabricated)
1 - 2232112 Hose Assembly (dealer fabricated)
1 - 2253035 Hose Assembly (for 834G only - dealer fabricated)

ACTION REQUIRED

See the attached Rework Procedure.

SERVICE CLAIM ALLOWANCES

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Product smu/age whichever comes first	Caterpillar		Dealer Suggested		Customer Suggested
Product smu/age whichever comes first	Parts	Labor Hrs	Parts	Labor Hrs	Parts	Labor Hrs
0-4000 / 0-24 months	100%	2	0	0	0	0
4001-6000 / 25-36 months	33 1/3%	1	0	0	50%	1
NOTE: This is a 2?hour job.

PARTS DISPOSITION

Handle the parts in accordance with your Warranty Bulletin on warranty parts handling.

Attach. (1-Rework Procedure)

Rework Procedure

Relocate the check valve and add the necessary fittings and hoses per the attached illustrations. This change may cause the fan to run continuously at a slow speed until the axle temperature rises and the controls trigger the fan to run at maximum speed.

Illustration 1

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Parts List for Group 1 Machines (2TW1-344, 6GZ1-Up) as shown in Illustration 1
Item	Part Number	Qty	Description
1	1947276	1	Hose Assembly
2	6V5258	1	Adapter
2	3D2824	1	O-Ring Seal
3	7M8485	2	O-Ring Seal
3	8C9029	1	Union
4	-	-	(Existing) Check Valve
5	6V8716	1	Connector
	6V9746	1	O-Ring Seal
	7M8485	1	O-Ring Seal
6	1234021	1	Hose Assembly
7	6V-9746	4	O-Ring Seal
8	6V-8990	1	45 Degree Elbow

Remove the existing hoses, seals and fittings from connections B to C and from connections A to D. Do not discard the existing check valve.
For 6GZ1-Up machines, remove the union assembly at connection C. Install a new 45-degree elbow (8) and seal (7) where the union was removed.
Install the new Hose Assembly (1) from B to C, as shown in Illustration 1. Use a new seal (7) at both ends of the hose.
Install new adapter assembly (2) and union assembly (3) at connection A. Install the existing check valve (4). The check valve should flow to connection D and away from connection A. Install new connector assembly (5). Install the new hose assembly (6) to connection D, as shown in Illustration 1. Use a new seal (7) at connection D. Illustration 1 shows the finished installation.

Illustration 2

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Parts List for Group 2 Machines (2TW345-Up, BNH1-591, BPC1-144) as Shown in Illustration 2
Item	Part Number	Qty	Description
1	2232112	1	Hose Assembly
2	6V5258	1	Adapter
2	3D2824	1	O-Ring Seal
3	7M8485	2	O-Ring Seal
3	8C9029	1	Union
4	-	-	(Existing) Check Valve
5	6V8716	1	Connector
	6V9746	1	O-Ring Seal
	7M8485	1	O-Ring Seal
6	2232111	1*	Hose Assembly (988G)
6	2253035	1*	Hose Assembly (834G)
7	6V9746	2	O-Ring Seal
8	6V8791	1	Tee
8	6V9746	3	O-Ring Seal

* Fabricate only the 988G Hose Assembly or the 834G Hose Assembly.

Remove the existing hoses, seals and fittings from connections B to C and from connections A to D. Remove the existing tee at B. Do not discard the existing check valve.
Install the new tee and seals (8) at connection B. Install the new hose assembly (1) from B to C, as shown in Illustration 2. Use a new seal (7) at the end of the hose near connection (C).
Install new adapter assembly (2) and union assembly (3) at connection A. Install the existing check valve (4). The check valve should flow to connection D and away from connection A. Install new connector assembly (5). Install the new hose assembly (6) to connection D, as shown in Illustration 2. Use a new seal (7) at connection D. Illustration 2 shows the finished installation.

Illustration 3 - Left side view of cooler core

Additional contributors to core failure can include reverse installation of the core bypass check valves (1) or reverse connection of the hoses to the cooler group (3). Verify that the check valves located just outside of the core face allow flow from the front to the rear of the cores, as they are oriented in the machine. The arrow on the check valve should be checked to make sure that the direction matches Illustration 3. Verify that the hoses are connected such that flow from the pump enters the fan motor (for the rear circuit) and filters before entering the cores.

NOTE: Disabling the system in Caterpillar Electronic Technician (ET) or unplugging the solenoid valve will cause oil to be pumped continuously through the core for the rear axle circuit. The fan motor will also run continuously at maximum speed. This can lead to core and/or fan motor seal failures when the oil is cold. Verify that the axle oil cooler attachment is enabled in Caterpillar Electronic Technician (ET).