the full electronic 4R44-55 is similar

Stall Speed Test
NOTE: Line pressure test MUST be performed prior to stall speed test.

The stall test checks converter one-way clutch operation and installation, the holding ability of the forward clutch, reverse clutch, the low reverse bands, the planetary one-way clutch and engine performance. Refer to stall speed specifications listed in Specifications in this section.

STALL SPEEDS Vehicle Drive Engine Converter Size Stall Speed RPM
Min. Max.
Aerostar 4x2
AWD 4.0L 10-1/4 In. 2550 2950
Aerostar 4x2 3.0L 10-1/4 In. 2720 3165




Stall Speed Diagnosis Chart

STALL SPEEDS RANGE SOURCE ACTION
Too high in (D)/D/R. · Vacuum system.
· Check and service vacuum system.

· Low main control pressure.
· Line pressure test. Check and clean main control valve body. Replace main control to case gasket. Check or service pump.

Too high in R only. · Low reverse servo, band damaged.
· Check engine braking in 1. If not OK, service or replace low/reverse servo and band as required.

· Reverse and high clutch damaged.
· If low/reverse servo OK, check and service reverse and high clutch.

Too high in (D)/D only. · Overdrive one-way clutch or rear one-way clutch damaged.
· Check engine stall speeds in 2 and 1. If OK, service overdrive or rear one-way clutches. Clean transmission.

Stall speed below spec range
problem with torque converter, one way clutch or engine performance



The test should be done only with the engine coolant and transmission fluid at proper levels and at operating temperature.

WARNING: APPLY THE SERVICE AND PARKING BRAKE FIRMLY FOR EACH STALL TEST.

Find the specified stall rpm for the vehicle by referring to Specifications in this section. Use a grease pencil to mark the rpm on the dial of a tachometer.

Connect the tachometer to the engine.

CAUTION: Holding at stall speed for longer than 5 seconds could result in damage to internal transmission components.

CAUTION: If the engine speed recorded by the tachometer exceeds the maximum limits given in Specifications, release the accelerator pedal immediately, because clutch or band slippage is indicated.

In each of the following ranges, (D) D, 2, 1, R, press the accelerator pedal to the floor and hold it just long enough to let the engine get to full rpm. While making this test, do not hold the throttle open for more than five seconds at a time.

Note the results in each range.

After each range, move the gearshift selector lever to N (neutral) and run the engine at 1000 rpm for about 15 seconds to cool the torque converter (7902) before making the next test.

 

Are the 'Stall Speed RPM' figures a range? (i.e. 2550 2950)

Also, can we assume the same figures are true for the E4WD versions?

Thanks for the detailed info! Almost afraid to go try this - sometimes ignorance is bliss.

 

stall speeds are a Min. Max. range

great for troubleshooting engine performance issues, i.e. is it running right? miss shows up very quickly.
also tests torque converter and some bands, clutch packs and valve body performance

best performed with lots of clear room in front of rig especially if condition of parking brakes or foot brakes in question

 

Thanks for posting the instructions. I wonder about a couple of things.

First, it seems these tests may be pretty hard on the transmission, so maybe they should not be done too often, or only on transmissions that are suspected of already having problems and other tests are not conclusive.

Second, a lot of the test failures seem to indicate pretty bad problems, requiring major work. (I think band or clutch replacement is pretty major, but I've never done them before, so I could be wrong.)

 

So do you need a code reader hooked up for this test, or will the tranny throw a code if there is something wrong with it that you read after the test.

Not quite sure what you are getting at with this post 96?