Case drain and heat exchanger
The pump and motor require case drain lines to remove hot fluid from the system. The pump and motor
drain from the topmost port to ensure the cases remain full of fluid. The motor case drain can connect to
the lower drain port on the pump housing or it can tee into the case drain line upstream of the heat
exchanger. A heat exchanger with bypass valve cools the case drain fluid before it returns to the
reservoir.
The schematic below shows the function of a hydrostatic transmission using an TMP axial variable
displacement pump with electric proportional displacement control (EDC) and an TMM fixed
displacement motor with integrated loop flushing device.
TMM with TMP EDC
A
A
B
B
L2
M3
M3
M5
M4
TMM
TMP
M2
L2
S
M2
M10
L1
C2
C1
M1
L1
M1
Legend:
A, B – System ports: Ø 25.4 mm
L1, L2 – Case drain ports: M22x1.5
M1, M2 – System A/B gauge ports: M12x1.5
M3 – Charge gauge port, after filtering: M12x1.5
M4, M5 – Servo gauge ports: M12x1.5
M10 – Charge pump inlet pressure port: M12x1.5
S – Charge inlet port: M42x2
Service Manual
TMM Transit Mixer Axial Piston Motor, Size 070/084/089
Introduction
L1211037 • Rev AC • Apr 2014
9
