
Most automatic transmissions are electronically controlled; electrical solenoids are used to
control the hydraulic fluid. The shift solenoids are regulated by an electronic control
module. Shift timing is regulated through sensor feedback information provided to the
electronic controller.
On older transmissions there are two pressures that control the shift valves. One is the
governor pressure which is affected by vehicle speed. The other is the modulator pressure
which is affected by intake manifold vacuum or throttle position. Governor pressure rises
with an increase in vehicle speed, and modulator pressure rises as the throttle is opened
wider. By responding to these two pressures, the shift valves cause the up shift points to
be delayed with increased throttle opening to make the best use of the engine's power
output.
Older transmissions also make use of an auxiliary circuit for downshifting. This circuit may
be actuated by the throttle linkage, vacuum that actuates the modulator, or by a cable or
solenoid. It applies pressure to the downshift surface on the shift valve or valves.
The transmission modulator also governs the line pressure, used to actuate the servos. In
this way, the clutches and bands will be actuated with a force matching the torque output
of the engine.
Содержание TrailBlazer
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Страница 26: ...Fig 3 Typical body and undervehicle maintenance locations Refer to chart for descriptions ...
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Страница 59: ...Cylinder head bolt removal and installation 32 Remove and discard the bolts from the cylinder head ...
Страница 175: ...Spring free length check Valve spring squareness check ...
Страница 192: ...Front of piston mark ...
Страница 361: ...5 3L Engine Except Saab Underhood Fuse Block 2003 2005 Early Production ...
Страница 469: ...Removing the outer band from the CV boot Removing the inner band from the CV boot ...
Страница 470: ...Removing the CV boot from the joint housing Clean the CV joint housing prior to removing boot ...
Страница 471: ...Removing the CV joint housing assembly Removing the CV joint ...
Страница 472: ...Inspecting the CV joint housing Removing the CV joint outer snap ring ...
Страница 473: ...Checking the CV joint snap ring for wear CV joint snap ring typical ...
Страница 474: ...Removing the CV joint assembly Removing the CV joint inner snap ring ...
Страница 475: ...Installing the CV joint assembly typical ...
Страница 506: ...Tie Rod End Removal Installation Inner Tie Rod End To Remove Inner tie rod assembly Magnasteer ...
Страница 553: ...9 Torque the lug nuts to specification 10 Lower the vehicle ...
Страница 556: ...Toe in Frame Misalignment Frame misalignment ...
Страница 588: ...Bleeding caliper ...
Страница 596: ...Inboard brake pad removal and installation 10 Remove the inboard brake pad from the brake caliper ...
Страница 624: ...Manifold gauge set components Refrigerant recovery recycling station ...
Страница 662: ...Lower instrument panel retaining volts 25 Remove the lower retaining bolts from the instrument panel I P ...
Страница 676: ...A C Specifications ...
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