Suburban 3/4 Ton 4WD V8-305 5.0L (1986)
Fig. 8 Rotary valve components
The rotary valve assembly includes the valve body, valve spool and stub shaft assembly. All these parts are precision units and are hydraulically
balanced at the factory. Under no circumstances are parts in this unit to be replaced or interchanged with other parts or units. If unit parts are scored or
damaged the entire rotary valve assembly is to be replaced. The O-ring should be replaced only if the gear squawks.
1.
To replace the valve spool dampener O-ring, work spool spring into bearing diameter of stub shaft and remove spool spring.
2.
Tap end of stub shaft gently against workbench to remove valve spool. The diametrical clearance between the valve body and spool may be as low
as .0004 inch. The slightest cocking of the spool may jam it in the valve body.
3.
Remove valve spool dampener O-ring.
4.
Install new O-ring in valve spool groove, then lubricate seal in automatic transmission fluid. Do not allow seal to twist in groove.
5.
With notch end of spool towards valve body, install spool, aligning spool notch with pin in stub shaft,
Fig. 8.
6.
Because of the small clearance between spool and valve body, extreme care must be taken when assembling these parts. Push spool evenly and
slowly with a slight oscillating motion until spool reaches drive pin. Before pushing spool completely in, make sure dampener O-ring seal is evenly
distributed in spool groove. Slowly push spool completely in, with extreme care taken not to cut or pinch O-ring seal.
7.
Slide spool spring over stub shaft and work spring into position.
Install Rack-Piston Worm & Valve
Fig. 24 Worm shaft & rotary valve components
