Allison Transmission 3000 Mechanic's Tips page 48

c. Performing a Transmission Stall Test.
1. Start the engine. While in neutral let the transmission warm to normal
operating temperature:
— Sump temperature 71–93°C (160–200°F)
— Converter out temperature 82–104°C (180–220°F)
2. Determine the hot transmission fluid level and adjust as necessary.
3. Turn OFF all engine accessories.
4. Place the Allison DOC™ diagnostic tool in clutch test mode. Use the shift
selector to select 4
the transmission driveline. Do not perform a transmission stall test in
reverse.
CAUTION: To help avoid transmission or driveline damage, full
throttle stall tests must not be performed in R (Reverse) range, all
models, or low ranges, 7-speed models.
5. Notify personnel in the area to keep clear of the vehicle.
6. Slowly increase engine rpm until engine speed stabilizes.
7. Record engine speed.
CAUTION: The transmission stall test procedure causes a rapid rise in
transmission fluid temperature that can damage the transmission. Never
maintain a stall condition once engine speed stabilizes or converter out
(to cooler) temperature exceeds 150°C (300°F). During a stall condition,
converter out temperature rises much faster than the internal (sump)
temperature. Never use sump fluid temperature to determine the length
of the stall condition. If the stall test is repeated, do not let the engine
overheat.
8. Record converter out (to cooler) temperature.
9. Reduce the engine speed to idle and shift the transmission to neutral.
10. Raise engine speed to 1200–1500 rpm for 2 minutes to cool transmission
fluid.
11. At the end of two minutes, record converter out (to cooler) temperature.
12. Proceed to the Paragraph g. Neutral Cool-Down Check Procedure.
th
range. Using 4
47
th
range reduces the torque imposed on