AUTOOL AS505 Optical Transmission Fluid Tester
US$49.00
- Optical Transmission-Fluid Screening
- Photoelectric Transmittance Probe
- Temperature + Status Display
- 800 mm Flexible Hose
- Optical Transmission-Fluid Screening: Measure automotive transmission-fluid transmittance and temperature before maintenance decisions.
- Photoelectric Transmittance Probe: Use the photoelectric probe to screen changes in fluid transparency linked with impurities or deposits.
- Temperature + Status Display: View oil temperature, transmittance, an analog bar, and OK, warning, or replacement guidance on the 2.8-inch backlit screen.
- 800 mm Flexible Hose: Reach service points with the oil-resistant, oxidation-resistant Teflon probe.
- Optical Transmission-Fluid Screening: Measure automotive transmission-fluid transmittance and temperature before maintenance decisions.
- Photoelectric Transmittance Probe: Use the photoelectric probe to screen changes in fluid transparency linked with impurities or deposits.
- Temperature + Status Display: View oil temperature, transmittance, an analog bar, and OK, warning, or replacement guidance on the 2.8-inch backlit screen.
- 800 mm Flexible Hose: Reach service points with the oil-resistant, oxidation-resistant Teflon probe.
- 3-Year Warranty Main unit 3 years · Accessories 1 year
- 90-Day Returns Eligible returns within 90 days
- Official Store Genuine products · Direct support
AUTOOL AS505 · Transmission Fluid Transmittance Tester
Inspect ATF Condition with Optical Context
Screen transmission-fluid transparency and temperature before deciding the next maintenance step. AS505 uses a flexible 800 mm probe to reach service points and shows transmittance, an analog bar, fluid temperature, and status guidance on one backlit display. The optical reading is service context rather than a stand-alone replacement decision.
- ATF Transmittance Screen
- Fluid Temperature Context
- 800 mm Flexible Probe
- 2.8-Inch Backlit Display
- 6 V Battery Power

Key Features
Transmission Fluid Tester: Transmittance and Temperature Together
High-Precision Optical Transmittance Probe
The integrated photoelectric transceiver sensor probe helps provide stable measurement feedback when checking transmission fluid transmittance.
800mm Flexible Hose Probe
The 800mm Teflon hose probe offers flexible access during testing and is resistant to oil, oxidation, and corrosion for longer service life.
Oil Temperature Display
The built-in temperature sensor displays the current transmission fluid temperature and supports °C / °F unit switching.
2.8-inch Backlit LCD
The high-definition backlit LCD makes readings easier to view in daylight, dim workshop areas, or nighttime conditions.
Clear Result Indicators
The screen shows transmittance, analog bar graph, OK, warning, and suggested replacement indicators to help users interpret the result quickly.
Comfortable Handheld Design
The silicone-lined handheld portion provides a comfortable grip, while the lightweight body supports easy single-handed operation.
Transmission Fluid Checks
AS505 measures automotive transmission fluid transmittance and temperature.
Portable Battery Power
The 175 × 72 × 29mm tester uses four 1.5V batteries for 6V operation.
Transmission Fluid Testing
AS505 is mainly used to test automotive transmission fluid transmittance and oil temperature. Reduced transmittance may be related to impurities, deposits, or metal contamination in the fluid.
6V Battery Power
The tester uses 4 × 1.5V AAA batteries for a 6V operating voltage. Install batteries with the correct polarity before powering on.
Auto Power-Off
The tester automatically powers off after about 5 minutes of no activity. Long press the power key to turn the tester on or off manually.
3 Years Warranty Support
Main unit: 3-year warranty. Standard accessories: 1-year warranty. Warranty Policy.
Service Workflow
Reach, Read and Clean the Probe
Install Batteries And Power On
Open the rear battery cover, install 4 × 1.5V AAA batteries with correct polarity, then long press the power key for more than 2 seconds.
Wipe The Probe Clean
Before each measurement, wipe the probe tip clean so old oil or dirt does not affect the transmittance reading.
Check Temperature Condition
Make sure the engine temperature is below 60°C. Press the temperature key if you need to switch between °C and °F.
Submerge The Probe
Place the testing probe into the transmission fluid. Keep the probe properly immersed during measurement.
Press Test And Read Result
Press the test button. The interface displays the transmission fluid transmittance and current fluid temperature.
Simple Sampling Procedure
Clean the probe, immerse it in the transmission fluid, then start the test and read the result.
Safe Use
Confirm Fluid Fit Before Testing
Engine Below 60°C
Before testing, make sure the engine temperature is below 60°C. This helps keep the measurement process within the recommended operating condition.
Suggested Test Interval
It is recommended to check transmission fluid condition every 5,000-10,000 km, especially before deciding whether transmission fluid service is needed.
Clean The Probe First
Wipe the test probe clean before each measurement. Residual oil, dirt, or contamination on the probe may affect the reading.
Use the Results to Plan the Next Check
Use the condition score to screen and compare a clean, representative transmission-fluid sample; use the specified tests when viscosity, wear metals, contaminants, or remaining service life must be assessed.
Model Comparison
Choose the Right Fluid Test Method
Model Guide
Choose one or more models. AS505 is selected by default.
| Product name | AS501 Brake Fluid Tester | AS502 Brake Fluid Tester | AS503 Engine Oil Quality Tester | AS505 Transmission Fluid Tester | AS506 Brake Fluid Boiling Point Tester | AS507 Power Steering Fluid Tester | AS509 Coolant Boiling Point Tester |
|---|---|---|---|---|---|---|---|
| Test Method & Application | |||||||
| Detection Technology | Pressure Boost Detection Technology | Water-content screening; no hydraulic pressure generation or measurement | Optical Probe Technology | Optical Probe Technology | Sample Heating Technology | Optical Probe Technology | Sample Heating Technology |
| Operating Principle | Brake Fluid (Water Content) | Brake Fluid (Water Content) | Engine Oil (Transmittance) | Transmission Fluid(Transmittance) | Brake Fluid (Boiling Point) | Steering Fluid (Transmittance) | Coolant |
| Test Mode Selection | Normal Mode | Normal Mode/Expert Mode | Gasoline Engine/Diesel Engine | Automotive Transmission Fluid | Normal Mode/Brand Mode | Automotive Steering Gear | Normal Mode/Brand Mode |
| Boiling Point Reference Value | × | × | × | × | ✓ | × | ✓ |
| Normal Mode | 6 Types ENV-4、ENV-6 DOT3、DOT4、DOT5、DOT5.1 | 3 Types DOT3、DOT4、DOT5.1 | × | × | DOT3, DOT4 and DOT5.1 (procedure-confirmed selections) | × | 23 Coolant Brands For ACDELCO、BASF、BOSCH、CASTROL、ENGINE_ICE、EVANS、FORD、HONDA、JOHN_DEERE、KUNLUN、MOBIL、MOPAR、NISSAN、OMTECH、PEAK、PRESTONE、RECOCHEM、SHELL、SKI-DOO、ZEREX、STAR_BRITE、TOTAL、TOYOTA |
| Measurement & Response | |||||||
| Temperature Unit Switching | × | × | ℃/℉ | ℃/℉ | ℃/℉ | ℃/℉ | ℃/℉ |
| Temperature Measurement Range | × | × | 0-85℃ 0-185℉ | 0-85℃ 0-185℉ | 0-320℃ 0-608℉ | 0-85℃ 0-185℉ | Diluted Coolant Boiling Point Range: 100°C~120°C(212°F~248°F) Original Manufacturer Coolant Boiling Point Reference Range 106°C~191°C(221°F~376°F) |
| Test Duration | 10s Response | 10s Response | 10s Response | 10s Response | 16s Response | 10s Response | 20~40s Response |
| Display, Probe & Power | |||||||
| Backlit Display Screen | 1.8-inch | 2.8-inch | 2.8-inch | 2.8-inch | 1.54-inch | 2.8-inch | 1.6-inch |
| Test Cable Length | 26cm | 26cm | 80cm | 80cm | 4cm | 80cm | 130cm |
| Power Supply Voltage | 3V | 6V | 6V | 6V | 12V | 6V | 10-14V |
| Hose Material | Iron Oxide | 304 Stainless Steel | Teflon | Teflon | × | Teflon | × |
Manual & Support
Find the Manual and Fluid-Test Guidance

AUTOOL AS505 User Manual
Open the PDF manual for AUTOOL AS505 transmission-fluid testing, optical-probe use, temperature display, result interpretation, battery operation, probe cleaning and troubleshooting support.

Package Contents
See What Comes in the Box
- Main UnitAUTOOL AS505 transmission fluid tester with integrated 800mm probe
- Retail BoxAUTOOL AS505 product package box
- ItemUser Manual AUTOOL AS505 user manual for setup, display, battery installation, operation, and warranty information
- PackageNote Accessories. Batteries are not listed in the package image, so prepare 4 × 1.5V AAA batteries if needed.
Buyer Questions
Fluid Fit, Method and Result Questions
What Does The AUTOOL AS505 Test?
AS505 tests automotive transmission fluid transmittance and displays transmission fluid temperature. It helps users assess fluid clarity, possible contamination, deposits, and whether service attention may be needed.
Is AS505 An ATF Exchanger Or A Fluid Tester?
AS505 is a transmission fluid tester. It is used to check transmission fluid transmittance and temperature. It does not exchange, flush, drain, or refill transmission fluid.
How Often Should I Test Transmission Fluid With AS505?
It is recommended to test transmission fluid once every 5,000-10,000 km. Testing frequency can also depend on vehicle mileage, driving conditions, transmission behavior, and maintenance schedule.
How Do I Use The AS505?
Install batteries, power on the tester, wipe the probe clean, confirm the engine temperature is below 60°C, submerge the probe into transmission fluid, press the test button, and read the transmittance and temperature result on the LCD.
What Do OK, Warning, And Suggested Replacement Mean?
OK indicates transmittance is between 100% and 50%. Warning indicates transmittance is between 50% and 30%. Suggested replacement appears when transmittance is below 30%. Use these results as a service reference together with vehicle condition and workshop judgment.
Can AS505 Test Engine Oil, Brake Fluid, Or Power Steering Fluid?
AS505 is designed for automotive transmission fluid testing. For engine oil transmittance, choose AS503. For brake fluid water content, choose AS501 or AS502. For brake fluid boiling point, choose AS506. For power steering fluid transmittance, choose AS507.
What Temperature Conditions Should I Follow?
The tester operating temperature is -10°C-60°C. The transmission fluid temperature display supports 0-85°C / 0-185°F. Before measurement, the engine temperature should be below 60°C.
What Power Supply Does AS505 Use?
AS505 uses 6V power from 4 × 1.5V batteries. Open the rear battery cover, install the batteries with correct polarity, and close the cover securely before use.
What Is Included In The AS505 Package?
Package contents: AS505 main unit with built-in probe, retail box, and user manual.
Why Should The Probe Be Wiped Clean Before Testing?
The optical probe reads fluid transmittance. Oil residue, dirt, or contamination left on the probe may affect measurement feedback, so the probe should be wiped clean before each measurement.
How Long Is The Warranty?
Main unit: 3-year warranty. Standard accessories: 1-year warranty. Warranty Policy.
Who Should I Contact For AS505 Setup Or Model Selection?
Contact AUTOOL Store if you need help with AS505 setup, transmission fluid testing, result interpretation, package confirmation, or choosing between AS502, AS503, AS505, AS506, and AS507.

























Robert ✓ Verified Purchase –
Durability: Excellent.
Durability: Excellent.
Performance: Precise.
Excellent, very reliable product. I tested it several times and it exceeded my expectations in every test.
Daniel ✓ Verified Purchase –
Excellent.
Excellent. With this oil gauge, I can check the condition of my automatic transmission fluid. It gives me the remaining fluid life percentage. I recommend it.
ABDULHADI AL JUHANI ✓ Verified Purchase –
Great customer service for excellent products.
Great customer service for excellent products.