ROD 8Y2281 - Caterpillar

Escaping fluid under pressure, even a pinhole size leak, can penetrate body tissue, causing serious injury, and possible death. If fluid is injected into your skin, it must be treated immediately by a doctor familiar with this type of injury.Always use a board or cardboard when checking for a leak.
Personal injury can result from hydraulic oil pressure and hot oil.Hydraulic oil pressure can remain in the hydraulic system after the engine has been stopped. Serious injury can be caused if this pressure is not released before any service is done on the hydraulic system.Make sure all of the attachments have been lowered, oil is cool before removing any components or lines. Remove the oil filler cap only when the engine is stopped, and the filler cap is cool enough to touch with your bare hand.
Care must be taken to ensure that fluids are contained during performance of inspection, maintenance, testing, adjusting, and repair of the product. Be prepared to collect the fluid with suitable containers before opening any compartment or disassembling any component containing fluids.Refer to Special Publication, NENG2500, "Dealer Service Tool Catalog" for tools and supplies suitable to collect and contain fluids on Cat products.Dispose of all fluids according to local regulations and mandates.
Introduction
The torque converter inlet relief valve is used to supply a constant pressure of oil to the torque converter. The inlet relief valve supplying constant pressure allows the torque converter to transmit torque between the engine and the planetary transmission. The torque converter inlet relief valve is located beneath the transmission hydraulic control relief valve on the left side of the transmission. The torque converter inlet relief valve is nonadjustable. Required Tools
Illustration 1 g01089423
Required tooling
Table 1
Required Tools
Tooling Item Part
Number Description Qty
A A1 8T-0855 Pressure Gauge 1
A2 6V-3989 Fitting 1
A3 6V-4143 Quick Connect Coupler 2
A4 177-7861 Hose As 1 Testing Procedure
Testing The Torque Converter Inlet Pressure
Illustration 2 g03147684
(1) Torque converter inlet relief pressure
(2) Torque converter inlet pressure relief valve The relief pressure of the torque converter inlet can be measured at pressure tap (1). Pressure tap (1) is located on the transmission hydraulic control relief valve.
Install Tooling (A) on pressure tap (1).
Start the engine.
Increase the oil temperature to 47 °C (116 °F).
Operate the engine at low idle. Observe the pressure gauge. The torque converter inlet pressure must be within the values that are shown in Systems Operation, Testing and Adjusting, "Power Train Pressures".
Operate the engine at high idle. Observe the pressure gauge. The torque converter inlet pressure must be within the values that are shown in Systems Operation, Testing and Adjusting, "Power Train Pressures".
Shut off the engine. Note: If the pressure is outside the specifications, test the pump supply pressure on the oil filter bypass valve. Refer to Specifications, Systems Operation, Testing and Adjusting, "Hydraulic Oil Contamination - Test". If the pump supply pressure is not correct, replace the torque converter inlet relief valve.