EVT F6 Allison Automatic Transmissions — practice test
F6 is the EVT Allison Automatic Transmissions test, and it is not a generic automatic-transmission exam. It assumes you know the 3000/4000 World Transmission clutch chart cold, know how the TCM decides what it decides, and know the fire-specific stuff - split-shaft pump shifts, output retarders, TES fluid rules - that never comes up on a light-duty test. Techs fail it because they study torque converters and planetaries, then get buried by pump-shift interlocks, prognostics, and fluid-spec questions they never saw coming.
Studying for EVT F6 (Allison Automatic Transmissions)? Overhaul Prep has 318 verified F6 questions written to the current task list — in the same formats the real exam uses (direct, Technician A/B, EXCEPT and most-likely-cause). Every answer comes with a written explanation, so you learn why instead of memorising a letter.
What's on the EVT F6 test
F6 is 50 to 100 multiple-choice questions in two hours, like every regular EVTCC test, weighted toward the 3000/4000 World Transmission family and WTEC III / Gen 4-5 electronic controls. Task areas cover general diagnosis, torque converter and hydraulic/mechanical powerflow, electronic controls and datalink diagnosis, the integral output retarder, PTO and split-shaft pump-shift operation, and fluid/maintenance. The real weight sits on the electronic controls and the fire-specific material - pump-shift interlocks, retarder behavior, TES fluid and prognostics. Expect heavy Technician A/B and "all of the following EXCEPT" formats.
EVTCC learning objectives for EVT F6
EVTCC builds the exam on its Reference Materials and Learning Objectives sheet for F6, Allison Automatic Transmissions. This is that sheet's outline, area by area, and the references it names. The sheet is dated February 2025.
What EVTCC says to study from
- NFPA 1910, 2024 edition (the NFPA 1911 section)
- Allison Mechanics Tips and Operator's Manuals for 1000/2000 and 3000/4000 EVS products - OM8471, MT7325EN, MT4015EN, MT7151EN, OM8491 and SA7497EN (shift selector)
- Allison TS2714EN Driveline Troubleshooting Manual
- Allison Service Tips - TI8807EN fluid and filter change, TI8591EN towing, TI8596EN Allison DOC, TI8952EN water and ethylene glycol, TI8989EN Allison DOC for 6th Gen controls
May include accepted-practice questions not found in the reference material.
The objectives, area by area
1Operating Principles9 items
Understand basic operating principles of Allison On-Highway transmissions as found in emergency vehicles to include:
- Hydraulic systems
- Clutch applications
- Clutch apply sequence
- Torque Converters
- Components of a torque converter
- Function of a torque converter
- Lock up clutch operation
- Driving Tips
- Downhill braking/using engine to slow the vehicle
- Proper towing techniques
- Coasting
- Cold weather starts
- Using hydraulic retarder
- Rocking out
- Normal PTO operation
- Model Numbers
- Location of number on transmission
- Water Pump Operations
- Shift sequence
- External Component Identification
- Shift selectors
- 3000/4000 series shift selector function
- Oil life monitor
- Prognostics enabled
- 3000/4000 series lockup mode
- 5th Gen Shift Inhibits
2Preventive Maintenance Support9 items
Understand preventive maintenance support of the Allison Transmission as found in emergency vehicles to include:
- PTO Installation
- Gaskets / sealing material
- Sealing compounds
- Dipstick Calibrations & Fluid Levels
- Fluid level checks
- Hot check
- Approved "TES" fluid types & compatibility
- Filter and fluid change intervals/mixtures
- Level check using shift selector
- Sump screen
- Dipstick Calibration
- Electronic fluid check procedure
- Filter recommendations
- Oil filter change procedures
- Oil life calculation
- Fluid Importance
- Identification of shift selector control
- Identification
- External linkage adjustments
- Driveline and Output flanges
- Phasing and angularity
- Output flange and seal
- Driveline inspections
- NFPA 1910 PM inspections
- NFPA 1910 Out-of-Service criteria
- NFPA 1910 service recommendations
- Periodic inspection and care
- vehicle cooling system check
- fluid leak repair
- Unusual sounds
- Exterior inspection
- Preparing vehicle for transmission installation
- Torque converter
- 1000/2000 Transmission Removal
3Troubleshooting Procedures6 items
Understand basic troubleshooting procedures. Identify problems that can be corrected in chassis and those requiring outside assistance to include:
- Driveline
- Driveline test (coast)
- Power train test (road speed)
- Engine test (RPM)
- Shift complaints
- Diagnosis
- Pump mode
- Shift inhibits
- PTO installations/operation
- Backlash adjustments
- External identifications
- Pressure port locations
- Signal port locations
- PTO pressure installation
- Fluid checks
- Impact of aerated fluid
- Fluid levels
- Noise occurring
- Fluid leak diagnostics
- Contaminations
- Breather maintenance
- NFPA 1911 leakage classes
- High fluid temperature
- Diagnostic reference material
- Code descriptions
- Power and ground
- Opens, shorts, short to ground
- Understanding schematics
- Welding precautions
- Range selection/ shift inhibit
- Mode indicator LED
- Troubleshooting - "no codes present"
- Checks and Adjustments
- Road test
4Electronic Controls3 items
Basic understanding of Allison electronic controls to include:
- Electronic control systems
- Electronic software series
- Power and ground connections
- Continuity checks
- TPS adjustments
- VIM fused circuits
- Welding caution
- Identification of WTEC 2 controls
- Identification of WTEC 3 controls
- Identification of 4th generation controls
- Identification of MY 09 4th generation controls
- Prognostics
- Oil life
- Wrench icon
- Trans Health driving requirements
- Shifts/Convergence
- Unadaptive
- Adaptive
- 3000/4000 series trouble codes
- Number of stored trouble codes
- Checking logged diagnostic codes
- Main codes and sub codes
- "Check trans" light action
- Service Indicator
- Mobile radio installation locations (RFI)
- Intermittent Faults
- "Do Not Shift" light
- 4th & 5th generation codes
- 5th gen speed sensor codes
- Datalink
- 6th gen
- hardware level
- cybersecurity
- 1000/2000 series
- Accessing diagnostic trouble codes (DTC)
- "Check transmission" light action
5Output Retarder2 items
Understanding of Allison Transmissions output retarders to include:
- Components
- Accumulator/Air System
- Accumulator locations
- Retarder locations
- Retarder operating parameters
- Fluid temperature
- 5th Gen controls
- Activation signal
- Oil cooler
- Safety feature
- Fluid level
- Fluid temperature
6Reference Materials1 item
Understanding Allison Transmission reference material to include:
- Understanding Allison Reference Material
- Owner assistance
- Stall test procedures
- Adjustment procedures for TPS and mechanical modulator
- Engine to transmission adaptation requirements
- Oil change intervals
- Speed sensors
- Allison website
From EVTCC's F6 sheet (PDF), read October 11, 2026. EVTCC revises its sheets one at a time, so the PDF is the current word. Learning objectives for all 22 EVT exams →
High-yield EVT F6 topics
The material that shows up year after year. If you're short on time, start here.
- Clutch chart for the 3000/4000: exactly two clutches apply per range. R = C3+C5, 1st = C1+C5, 2nd = C1+C4, 3rd = C1+C3, 4th = C1+C2 (direct 1.00:1), 5th = C2+C3, 6th = C2+C4. They test it as a diagnostic: slips in first AND reverse but is fine elsewhere means the shared clutch (C5) is the fault, not low main pressure. Memorize the chart and practice finding the common element.
- Torque converter failure modes as look-alikes. Stator one-way clutch SEIZED = strong launch, then overheating and no top speed (stator will not freewheel at coupling speed). Stator one-way clutch SLIPPING/freewheeling = sluggish off idle with no torque multiplication, but normal top speed and no heat. Stall speed high = slipping clutches or converter; stall low with no other symptom = the engine is down on power, not the converter.
- Electronic oil level check conditions, all of them: engine at idle, transmission in Neutral, vehicle stopped on level ground with the parking brake set, output shaft not rotating, and sump temperature inside the valid window (roughly 140-220 F). Display reads oL, then OK / LO / HI with a quart count - oL LO 02 means two quarts low. Miss one condition and you get an invalid-check code, not a level.
- Split-shaft pump shift sequence and NFPA interlocks. Complete stop, selector to Neutral, parking brake set, wheels chocked, make the pump shift (air pressure must be up), THEN select Drive and confirm the speedometer indicates road speed - that is what proves the driveline is turning the pump. Green indicators required in the cab (pump engaged, OK to pump) and at the pump panel. The fire/emergency calibration commands converter lockup in pump mode to keep converter slip from cooking the fluid.
- Integral output retarder: hydrodynamic, fluid filled, retarding torque roughly proportional to the SQUARE of output shaft speed. It is inhibited in Neutral, inhibited below a minimum output speed, and released when ABS activates. Its heat goes into the transmission fluid, out through the cooler, and into the engine coolant - which is why coolant temp climbs on a long retarder descent and why retarder units need more cooling capacity. NFPA requires an auxiliary brake at 36,000 lb GVWR and above.
- Fluid specs and prognostics. TES 389 is conventional; TES 295 / 468 / 668 are the full-synthetic specs (TranSynd), with TES 668 superseding 295. Prognostics (Oil Life, Filter Life, Transmission Health monitors) is only validated on TES 295/668 fills - and the monitors must be RESET after a fluid and filter service. 3000/4000 units carry two filters. Pink and milky fluid = coolant intrusion through the cooler, not normal new-fluid appearance.
Where techs lose points on EVT F6
Good technicians miss these — not from lack of skill, but because the question is built to catch them.
- "Put it in Park." Allison automatics on fire apparatus have no mechanical park pawl. Any answer that secures the apparatus for stationary pumping by selecting Park is wrong - the correct answer is parking brake set plus wheel chocks, and chocks are not optional.
- Assuming the retarder can hold the truck on a grade. It cannot. Retarding effort falls off with the square of speed, so it fades to nothing near zero output speed. Same trap in reverse: a complaint of "strong retarder at highway speed, almost none as it slows" is normal hydrodynamic behavior, not a defect - and rising coolant temp during retarder use is the cooling path working, not a bad retarder.
- Only worrying about low fluid. Overfill aerates the fluid, and foamy fluid drops main pressure, causing erratic shifts, slipping, and overheating - the same symptom set as underfill. When a question gives you foamy fluid plus overheating, do not reflex to "low level." Related: a valid level check requires a hot sump, so "check it cold right after startup" is always the wrong technician.
- Chasing a fault when the speedometer reads road speed while the truck is parked in pump mode. That is normal - the output shaft is turning the pump. And after a TCM swap, harsh shifts plus a high-reading speedometer is a calibration problem (wrong tire rev/mile or axle ratio), not a bad sensor or a failing clutch.
A study plan that works for EVT F6
Roughly two weeks of real preparation, in the order that actually builds on itself.
- Days 1-3: Fundamentals you cannot fake. Draw the 3000/4000 clutch chart from memory every morning until you can do it in under a minute, then work backward from symptoms (which clutch do these two failing ranges share?). Same block: converter elements - impeller bolted to the cover, turbine, stator with its one-way clutch - plus vortex vs rotary flow and the four stall-test outcomes.
- Days 4-6: Electronics. TCM inputs (input/turbine/output speed sensors as variable-reluctance pickups, TFT thermistor, throttle over J1939) and outputs (pressure-control variable-bleed solenoids, lockup, retarder modulation). Learn how the TCM verifies commanded range by comparing turbine to output speed, what DNS does and why, WTEC III two-digit main/sub codes vs Gen 4-5 SAE P-codes, and what Allison DOC is used for.
- Days 7-9: The fire-specific half, which is where the test is won. Split-shaft pump-shift sequence and every interlock condition, OK-to-Pump indicator logic, hot-shift vs constant-mesh PTO, pump-and-roll, retarder inhibits and cooling, and the full TES fluid/prognostics picture including monitor resets. If you only have time for one area, make it this one.
- Days 10-12: Drill in exam format only. Nothing but Technician A/B and EXCEPT questions until the wording stops fooling you, and log every miss by task area. Two days out, stop learning new material and re-drill your logged misses plus the clutch chart. Walk in able to recite the oil-level-check conditions and the pump-shift sequence cold.
Sample EVT F6 questions
Straight from the bank — answers highlighted, with the explanation underneath.
In an Allison electronically controlled automatic transmission, what is the primary purpose of the torque converter lockup clutch (TCC)?
- Provide a direct mechanical connection between the engine and transmission input, eliminating converter slip
- Multiply engine torque during initial acceleration while the converter is still slipping
- Circulate transmission fluid through the external cooler to carry converter heat away
- Apply the integral output retarder to provide hydrodynamic braking on a downgrade
Two technicians discuss the integral output retarder on an Allison transmission. Technician A says the retarder is a hydrodynamic device that uses transmission fluid to absorb vehicle energy and slow the truck. Technician B says because the retarder adds a large heat load, the apparatus must be equipped with an adequately sized transmission cooler. Who is correct?
- Technician A only
- Technician B only
- Both Technicians A and B
- Neither Technician
A midship split-shaft pumper with an Allison automatic will not complete a pump shift and the "OK TO PUMP" indicator will not illuminate. Which unmet requirement is the MOST likely cause?
- The transmission is not in Neutral and/or the parking brake is not set when the pump shift is attempted
- The output retarder is disabled and produces no braking when the pump shift is attempted
- The transmission fluid level is one quart high, just above the specified full level
- The J1587 diagnostic datalink has been left disconnected at the diagnostic connector
Ready to pass F6?
Get all 318 F6 questions plus timed full-length mock exams, a high-yield “must-know” filter, and readiness tracking that tells you when you're actually ready.
Start your 24-hour free trial