DEEP REDUCTION AIR SYSTEM: 8-SPEED “LL” MODELS ONLY
In addition to the various components of the Range Shift Air System, the Deep Reduction Air System uti- lizes a reduction cylinder and a separate dash- mounted Deep Reduction Valve OR the Master Con- trol Valve A-5015.
WHILE IN THE LO SPEED GEAR POSITION, the button can be moved FORWARD to operate in LO-LO. The “SP” Port of valve is OPENED when deep reduc- tion selection is made, supplying AIR to the Center Port of cylinder cover.
CONSTANT AIR from the air filter/regulator assem- bly is supplied to the reduction cylinder at the port on right side of cylinder cover. See Air System Sche- matics.
With the Deep Reduction Lever in the “OUT” posi- tion, the valve is OPENED and AIR is supplied to the Center Port of cylinder cover, moving the reduction piston forward to disengage deep reduction gearing. With the lever moved to the “IN” position, the valve is CLOSED and NO AIR is supplied to the Center Port. CONSTANT AIR from the air filter/regulator as- sembly moves the reduction piston rearward to en- gage reduction gearing.
Button FORWARD (“SPY’ Port OPENED)
NOTE: WHILE IN HIGH RANGE, the mechanical in- terlock of Master Control Valve prevents movement of Deep Reduction Button to the FORWARD position.
L e v e r t o “ O U (Valve OPENED) T ”
L e v e r t o “ I (Valve CLOSED) N ”
For models equipped with the Master Control Valve A-5015, AIR is supplied to the built-in deep re- duction valve ONLY WHILE IN LOW RANGE from tee fitting at the Low Range or “L” Port of slave valve. The insert valve (see page 37) MUST be installed in cylinder cover to provide the proper air flow needed to move the reduction piston in the cylinder. See schematic provided on Page 32. NOTE: The insert valve is NOT USED in the reduc-
tion cylinder cover of models equipped with the dash mounted Deep Reduction Valve. With the Deep Reduction Button in the REAR- WARD position, the “SP” Port of control valve is CLOSED and NO AIR is supplied to the Center Port of cylinder cover.
If the transmission fails to shift or shifts too slowly to or from LO-LO, the fault may be in the Deep Re- duction Air System or related components of the Range Shift Air System.
To locate the trouble, the following checks should be made with normal vehicle air pressure supplied to the system, but with the engine off. See CAUTION, Page 25. NOTE: It is assumed that correct PSI readings were
obtained from the air filter/regulator and all air lines have been checked for leaks.
For Models Equipped with the Deep Reduction Valve . . .
1. Air Supply (See Air System Schematics.) With the gear shift lever in neutral, loosen the connection at the INLET (End Port) of Deep Re- duction Valve until it can be determined that CONSTANT AIR is supplied to valve. Reconnect air line. If there is NO AIR, check for a restriction in line between the Deep Reduction Valve and slave valve, making sure this line is connected to tee fitting at the Supply or “S” Port of slave valve.
Button REARWARD (“SPY’ Port CLOSED)