Case 580SR Service Manual page 197

www.maskinisten.net
Copyright ©
SECTION 21 - TRANSMISSION 131
PRESSURE TESTING TORQUE CONVERTER AND COOLER CIRCUIT
All pressure and flow testing should be measured with an oil temperature of 82 - 93 °C.
For operating speed refer to each test.
Port 1 System pressure.
Z Engine set to 750 rpm minimum pressure 15 bar.
Z Engine set to 2200 rpm 19.6-23.1 bar.
Port 2 Torque converter in.
Z Engine set to 2200 rpm oil pressure range 5-11 bar.
Port 3 Torque converter out.
Z Engine speed 2000 rpm minimum pressure 2 bar.
Z Engine speed 2200 rpm maximum pressure 5 bar.
Port 4 Oil temperature converter out.
Z Normal operating temperature 80-90 °C.
Maximum temperature 120 °C.
Port 5 Oil temperature cooler out.
Z T.B.A.
Port 6 Lubrication pressure.
Z Engine speed 2000 rpm pressure range 0.8-2.0 bar.
HYDRAULIC OIL FLOWS
Oil flows to the pressure regulating valve, maintaining system pressure to the control valve and clutches at 20
bar.
Excess oil flow is bled to the converter system which is protected by a 10 bar safety valve.
Oil enters the converter through the converter blade cavity and exits in the passage between the turbine shaft
and pump drive.
Oil then flow to the external cooler.
Across the converter and the oil cooler system a by-pass valve is fitted; if the pressure difference is more than
4 bar, the valve will open. Excess oil is directed to the lubrication system.
This protects the system during start up from cold oil or at high rpm.
After leaving the cooler the oil is directed via a single fitting on the rear of the transmission to a series of tubes
and passages, to lubricate and cool the transmission bearings and clutches.
Oil is drawn up from the sump, via an internal strainer, through the inlet port of the hydraulic pump.
Oil is pumped out to the pressure filter.
Across the oil filter is a filter by-pass valve which will open if the pressure difference becomes higher than
4.3 bar.
The oil then gravity drains back to the transmission sump.