TM 5-3805-262-34
TRANSMISSION THEORY OF OPERATION (CONT)
Oil Flow with Shifting Spool in Reverse. Shifting spool is moved into body of trans-
mission control valve. Spool connects trimmer circuit, reverse clutch circuit, and
main pressure circuit. Oil flows from trimmer circuit through check valve into re-
verse clutch circuit. When oil in trimmer circuit flows into reverse clutch circuit,
pressure in trimmer circuit decreases and spring pushes trimmer plug to the right.
With compression on spring decreased, spool in main pressure regulator decreases
main pressure. Decreased main pressure gradually engages reverse clutch.
As clutch engages, pressure in clutch circuit increases. Pressure in trimmer circuit
also increases. Orifice and check valve in trimmer circuit prevent rapid increase in
pressure. As pressure in trimmer circuit slowly increases, trimmer plug moves to the
left and compresses spring on spool. As compression on spring increases, main pres-
sure returns to maximum to keep reverse clutch tightly engaged.
Shifting spool connects passages for low clutch and high clutch to oil sump.
Remainder of components in transmission operate same as described above in Oil Flow
in Neutral.
4-90
