TROUBLE HYDRAULIC PRESSURE DATA Pressure Tap Locations Two pressure tap plugs in the front pump cover are accessible via holes in the engine front mount front pump pressure is at the 6 o clock position and throttle valve TV pressure is at the 8 o clock position Test Preparation All tests can be made without driving the vehicle by simply raising the wheels 3 5 inches from the floor on stand jacks With pressure gauges installed perform the following preliminary steps Establish pressure gauges indicator needle rest positions at zero pressure Thoroughly warm up transmission Check transmission oil level Check linkage adjustment FRONT PUMP PRESSURES PSII Condition Range Selector Position R N D L At idle 16 Hg 81 98 47 57 47 57 71 82 At idle with vacuum hose disconnected 140 157 71 82 71 82 71 82 at balance tube Absence of front pump pressures results in no drive in any range see Diagnosis Guide as this pressure is required to apply the applicable clutch for a given range Common causes would be stuck pressure regulator valve broken or disengaged front pump shaft or missing plug from front end of front pump shaft which would divert converter in SHOOTING Moderately low front pump pressures in all ranges would indicate a restricted front pump in Failure of pressure to raise when disconnecting the vacuum hose or high pressures with the hose connected would indicate a stuck vacuum modulator valve defective vacuum modulator or collapsed hose Rear Pump Check With the rear wheels raised place the selector in D and accelerate the engine Front pump pressure should drop to approximately 0 5 psi at approximately 20 mph If pressure does not drop rear pump is disengaged or clogged or rear pump check ball not seating THROTTLE VALVE TV PRESSURES lPSll Condition R N D L Disconnect TV rod at carburetor and vacuum hose 0 0 52 54 66 77 at balance tube Depress accelerator to W O T By disconnecting TV rod at carburetor engine remains at idle speed throughout test Throttle valve pressure tests are of value in cases where the transmission shift points are not in accordance with the Shift Point MPH Chart If pressures are not as prescribed they may be raised or lowered by adjusting the position of the jam nut on the throttle valve assembly fig 6E 11 To raise TV pressure 3 psi back off the jam nut one 1 full turn This increases the dimension from the jam nut to the throttle valve assembly stop Conversely tightening the jam nut one 1 full turn lowers TV pressure 3 psi Smaller pressure adjustments can be made by partial turns of the jam nut The end of TV adjusting screw has an Allen head so the screw may be held stationary while the jam nut is moved