4L60 Part throttle 4-3 downshift

12/8/2004

8:30 AM

Page 251

Chapter 11

Transmission and Transaxle Circuits

251

Part Throttle 4-3 and Modulated Downshifts

Pressures Intake & decrease Converter & lube Mainline T.V. feed T.V. Modulated T.V. (M.T.V.) M.T.V. up M.T.V. down Governor Accumulator

Retainer & ball assembly located in case face

Fwd cl ACC Ex

Lo/rev Rev Lo/rev Fwd cl feed

Rev

12

D4

Fwd cl accum

Overrun 6

Ex

Lo overrun vl

Cooler

Reverse

3rd cl

Converter cl screen

4

Conv sig

Line pressure tap

Lo

Lo 1st

Decrease

Modulated T.V. up

Dr 3

Dr 2

Line

Bleed orifice

T.V. Rev

Gov

Ex

Ex

Ex

Ex

Ex

Modulated T.V. down

1-2 T.V.

1-2 shift

Filter

Ex

T.V.

Detent

Gov

Ex

3-4 shift

Dr 3

T.V.

Det

3-4 accumulator

Ex

Ex

Line bias

Ex

Mod. T.V. up

Mod T.V. dn Governor

3-2 control

4-3 T. V. limit

4th accumulator

Drive 3

2nd

2-4 servo

4th

2

Drive 4

Ex

Ex

Lo 1st

Pressure relief valve

Ex

Lo

3rd clutch

7

Overrun

Line

3rd acc

8

Det

4th

Bleed orifice Modulated T.V.

Pump

Sump

Conv sig

Drive 2

Pressure regulator valve

3-4 T.V.

T.V.

T.V. feed 1 D4

Part throttle

P.T. 4-3

Ex Ex

Det

3

M.T.V.

Overrun Throttle

T.V. plunger

Line boost

4-3 sequence

4th

2nd 4th accumulator

3-4 relay

Ex

Ex

Ex

4-3

10

Accum.

1-2 accumulator

Dr 4

Drive 4

P.T. dr 3

T.V.

Bleed orifice

4th signal

Intake

Ex 4th acc

Rnd 4 D3

Screen

Servo feed

R N D4 3 2 1

Line

2-3 T.V. Det

P

2-3 shift

Lo

Rev

Manual valve Ex

Bleed orifice

Overrun

Dr 4

Converter feed

Solenoid

D4

Lo 1st

Converter signal Ex

Ex

D4 Air bleed

Oil cooler

Abuse valve

Lo 1st

Ex

Drive 4

Governor

Fwd cl feed Air bleed

Governor

Converter cl apply

Ex

Rev

3rd clutch

Rev

Governor screen

Apply

Release

Lube

Lube

Ch11.qxd

Servo feed 4th acc 2nd

Figure 11-17. Part throttle downshift in the overdrive range. Which valves cause the shift valves to move? (General Motors)