CAP 4D7618 - Caterpillar

Illustration 6 g03627159
(12) Cover
(13) Torque converter outlet relief valve
Remove spring (16) and spacers (15) from spool (14) within the valve.
Illustration 7 g03627336
Torque Converter Outlet Relief Valve
(12) Cover
(14) Relief valve spool
(15) Spacers
(16) Spring
Add or remove spacers (15) from the pack of springs to attain the desired pressure.
Table 8
Spacers
Pressure Change for the Valve(1)
Description Thickness Pressure Change Location of Spacers
4M-1751
Spacer 0.41 mm
(.016 inch) 19 kPa
(2.7 psi) Outlet relief valve
5S-7001
Spacer 0.91 mm
(.036 inch) 40 kPa
(6 psi)
(1) Result of the addition of one spacer or the removal of one spacer to the valve.
Install spacers (15) and spring (16).
Install cover (12) and tighten the bolts.Torque Convertor Double Stall Pressure
Run the engine and warm the machine to operation temperatures. Engine coolant and hydraulic oil should be at normal machine testing temperatures.Note: Warm transmission oil and torque converter oil to the temperatures listed in table.
Table 9
Oil at Normal Operating Temperature
Transmission Oil Torque Converter Oil
83° 7°C (181° 12°F) 93° 17°C (199° 30°F)
Ensure that the parking brake is engaged. Select manual shift mode. Shift transmission to FOURTH SPEED, NEUTRAL.
At low idle shift the transmission to FOURTH SPEED, FORWARD.
Fully place the bucket in the racked back position.
Place engine in HIGH IDLE.
Stall until fully in the racked back position, and command full lift.
Once the engine speed stabilizes, Record the stabilized engine speed that occurs when the lift cylinders are extending.
Shift the transmission to FOURTH SPEED, NEUTRAL, and release throttle pedal.If the torque converter double stall speed is too high, the engine power output could be too high. (Not likely)If the torque converter double stall speed is too low, the engine may not be developing full power. There may be a parasitic load on the engine.Test for the Transmission Oil Pump Pressure
Before checking the Transmission Oil pump Pressure, verify the transmission neutral clutch solenoid modulating valve is functioning.Reference: Refer to the section "Test for the Transmission Clutch Solenoid Modulating Valve" in this document for the proper procedure.Also, verify the pressure difference between the transmission pump and the transmission neutral clutch is within specification.Reference: Refer to the section "Test for the Transmission Clutch Pressure" in this document for the proper procedure.
Perform the steps in the "Machine Set Up" and then continue to the following steps.
Attach tooling (A) or (B) on pressure tap (10).
Connect the machine to a laptop computer equipped with the latest version of Caterpillar Electronic Technician Cat ET. Establish communication.
In Cat ET, navigate to the "Diagnostics" drop-down menu and select "Diagnostics Tests". Expand the "Transmission ECM" section under "Available ECM(s)" and select "Transmission Main Relief Valve Test".
Follow the on-screen instructions through Cat ET to complete the pressure test. The test will automatically command the engine to a predefined speed and ask if the measured pressure is within certain limits for several test points.Adjustment for the Transmission Oil Pump Pressure
If the measured pump pressures do not meet specification, temporarily replace the "eMRV" and repeat the test through Cat ET. If the measured pump pressures are still NOT within specification after replacing the "eMRV", the transmission