Fav 900
Transmission / Transmission control unit
Transmission control unit functional sequence
A
General
Fav 900 chassis number 23/3001 and up
6.8.2001
1005
000005
A
a
1/4
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Transmission control unit functional sequence
Text-module
Transmission type ML 200
M
= Marschall, designer of this development
L
= Stands for the German term Leistungsverzweigung (= power splitting), mechanical and
hydrostatic power transmission
200
= Average power 200 bhp, 100 - 300 bhp is economically transmitted to the wheels.
Text-module
ML 200 transmission
The ML 200 transmission is a continuously variable transmission for forward and reverse travel.
Synchronised range shifting is integrated in the transmission.
Range I is for forward speeds from 0 to approx. 32 km/h.
Range II is for forward speeds from 0 to approx. 50 km/h.
Range I is intended for heavy traction work at low travel speeds, i.e. less than 12 km/h.
Range II is intended for use on roads (transporting applications). At 50 km/h the transmission ratio is
electronically matched to the engine speed. Should the electronic governor not engage, the tractor
runs at a max. travel speed of approx. 70 km/h.
Power transmission can be hydrostatic or mechanical or hydrostatic and mechanical.
Basically this means:
Slow forward travel = hydrostatic power transmission high / mechanical low
Fast forward travel = hydrostatic power transmission low / mechanical high
Detailed explanation: Chapter 1005 Reg. A - Transmission function schematic
Text-module
Hydrostatic power branch
The ML transmission unit is flexibly mounted in the transmission housing. The transmission housing is
also the oil reservoir for the hydrostatic drive.
Oil: STOU oil
Initial fill: approx. 85 l
Refill: approx. 65 l, e.g. at an oil change
Text-module
Functional sequence: Chapter 1005 Reg. C - Hydraulic circuit diagram
The lubricating pump (1P2) draws in oil via the intake filter (1Z1).
The temperature sensor (1S1 / B009) monitors the transmission oil temperature.
Oil flow through the oil cooler (1Z3) depends on the temperature.
This means that if the transmission oil is cold, little oil flows through the oil cooler, while most flows via
the bypass valve which opens when the pressure differential exceeds approx. 3.5 bar. The
transmission oil temperature is monitored by the temperature sensor.
The servopump (1P1) generates the system pressure for the ML control valves and the enhanced
control valves. The system pressure of approx. 25 bar is restricted by the pressure-relief valve with its
throttling port.
Text-module
ETNum-list
Contamination of the pressure filter is monitored by a pressure-operated switch (1S2 / So17) as a
function of the transmission oil temperature. If the transmission oil temperature is below 50
°
C, filter
contamination is not monitored.
The system uses different pressures.
1. System pressure for ML transmission control unit approx. 25 bar and enhanced pressure approx. 18
bar for rear PTO clutch, differential locks and cardan brake.
2. High pressure in ML transmission. Max. pressure-measuring point approx. 500 + 20 bar.
