57912 Shift valve and governor plug 12SV and 12GP Fig 519

This valve combination automatically controls and shifts the transmission from first to second or from second to first depending upon governor and throttle pressure. When governor pressure on the right hand governor plug side overcomes throttle pressure on the left hand 1-2 shift valve side, both

Fig. 5.18 Throttle pressure limiting valve (TPLV)

Fig. 5.17 Converter pressure valve (CPV)

Fig. 5.18 Throttle pressure limiting valve (TPLV)

Fig. 5.19 1-2 shift valve (1-2)SV, and 1-2 governor plug (1-2)GP in 1-2 upshift condition

1-2 governor plug and 1-2 shift valve move to the left thereby opening the line pressure port which delivers oil from the pump. Line pressure will now pass unrestricted through the valve to feed into the brake band servo. As a result an upchange occurs. If, in addition to the throttle pressure, kickdown pressure is introduced to the valve combination, gear upshifts will be prolonged. If '1' manual valve is selected, line pressure will be supplied to the governor plug chamber (large piston area) and the throttle spring chamber, preventing a 1-2 upshift. '1' manual position cannot be engaged at speeds above 72km/h because the 1-2 shift valve cannot move across, due to the governor pressure.

5.7.10 2-3 Shift valve and governor plug (2-3)SV and (2-3)GP (Fig. 5.20(a and b)) The 2-3 shift valve and governor plug control the gear change from second to top gear or from top to second depending upon governor and throttle pressure. As governor pressure exceeds throttle pressure, the shift valve and governor plug are pushed over to the left. This permits line pressure to pass through the valve so that it can supply pressure to the drive and reverse clutch piston, so that an upchange can now take place. When '2' manual valve position is selected, there is no pressure feeding to the shift valve which therefore prevents a 2-3 upshift.

Fig. 5.20(a and b) 2-3 shift valve (2-3)SV, 2-3 governor plug (2-3)GP, 3-2 control valve (3-2)CV, 3-2 kickdown valve (3-2)KDV and valve for direct and reverse clutch V(D + R)C
Do It Yourself Car Diagnosis

Do It Yourself Car Diagnosis

Don't pay hundreds of dollars to find out what is wrong with your car. This book is dedicated to helping the do it yourself home and independent technician understand and use OBD-II technology to diagnose and repair their own vehicles.

Get My Free Ebook


Post a comment