SH/T 0756-2005 Thermal stability evaluation method for manual transmission fluids (cyclic durability test method)

AI-translated method card — human verification pending. This is not an official translation of the standard. Unclear source values remain unverified; check the original standard and product certificate before use.

Card type: Test method

1. Method number / full name / English name / replacement relationship

• Standard number: SH/T 0756-2005
• Chinese name: Thermal stability evaluation method for manual transmission fluids (cyclic durability test method)
• English name: Standard test method for evaluating the thermal stability of manual transmission lubricants in a cyclic durability test
• Replacement relationship: not provided in the available source (the foreword only states modified adoption of ASTM D5579-01, and does not mention replacement of an old version of the standard)
• Adoption relationship: modified adoption of ASTM D5579-01 "Standard Method for Thermal Stability Cyclic Durability Test of Manual Transmission Fluids"
• Publication/implementation: published by 2005-04-11, implemented by 2005-09-01
• Issuing body: National Development and Reform Commission of the People's Republic of China
• Drafting organization: Lubricant Research and Development Center of PetroChina Company Limited
• Main drafters: Zhang Hongkui, Cai Jiyuan
• Custodian: Sinopec Research Institute of Petroleum Processing
• Proposed by: China Petrochemical Corporation

2. Applicable scope and non-applicability

• 1.1 This standard specifies a test method for evaluating the high-temperature thermal stability of heavy-duty manual transmission fluids using a Mack cyclic test machine.
• 1.2 It is applicable to evaluating the high-temperature thermal stability of manual transmission fluids.
• 1.3 The transmission is continuously switched between high speed and low speed, and the performance of the lubricant is evaluated by measuring the number of shift cycles before failure of the transmission synchronizer.
• 1.4 The correlation between the test results of this standard and the actual service results of truck transmissions has not yet been established. This test procedure can distinguish the quality of lubricants used in the same model of transmission.
• 1.5 Users are required to establish appropriate safety and health measures and formulate effective rules and regulations to ensure safe operation of the test.
• Non-applicable scope: no explicitly listed non-applicable clauses are provided in the available source.

3. Method principle

• 4.1 Before each test run, the transmission assembly is disassembled. All components, including the transmission gearbox, test oil circulation and heating system, must be thoroughly cleaned. A new synchronizer assembly, including inspected shift forks, friction discs and guide discs, is used to reassemble the transmission. Other components that are worn or damaged are replaced.
• 4.2 The assembled transmission is installed on the test bench.
• 4.3 According to the cleaning procedure, the transmission and lubricating oil circulation system are cleaned with test oil.
• 4.4 The cleaning lubricant is drained, and the specified amount of test oil is measured and added to the transmission.
• 4.5 The transmission is started and run at low speed so that the test oil temperature reaches the specified test value.
• 4.6 The transmission automatically cycles between low speed and high speed. The test ends when two nonsynchronous shifts occur in the synchronizer or when the required test cycles are reached. The number of cycles from high speed to low speed is recorded once per hour.
• 4.7 The transmission is disassembled and the test parts are removed; the wear amounts of the shift fork and friction disc are measured, and sediment evaluation is performed to reach the test conclusion.

4. Reagents and materials (purity / preparation)

• 7.1 Test oil: this test requires 45.4 L test oil.
• 7.2 Aviation washing gasoline: conforms to SH 0114, used for cleaning test specimens.
• 7.3 Kerosene: conforms to GB 253, used for cleaning the test oil circulation system.
• Reference oils (10.2): this test method uses two reference oils, namely a passing reference oil (high-quality oil) and a failing reference oil (low-quality oil).
• Purity/preparation details: not provided in the available source.

5. Instruments and equipment

• 6.1 The test equipment uses a Mack cyclic test machine. The instruments and materials used by this equipment shall meet the performance and specification requirements in Table 1.
• 6.2 Test transmission: Mack T2180, part number IIKBA51431 (see Figure 1). Before being used as a test transmission, some components need to be removed and installed, as listed in Table 2.
• 6.3 Connection between transmission and power source: the transmission uses an electric motor as the power source; the motor is connected to the transmission through a belt and drive shaft and drives the transmission to rotate (see Figure 2).
• 6.4 Drive system: the motor drives the drive shaft through a belt; the drive shaft is connected to the transmission output shaft and drives the transmission to rotate. The shift fork pushes the synchronizer through a pneumatic piston. The universal joint at the end of the drive shaft is connected to the spline at the output end of the transmission output shaft, and the drive shaft and the transmission output shaft form an included angle (see Figure 2).
• 6.5 Test oil circulation system: the test oil heater system heats the test oil to 121℃±2.7℃ (250℉±5℉) and maintains this temperature during the test. The total volume of the test oil circulation system is 19.9 L. The lubricating oil level in the transmission is at the lower edge of the return oil hole. The layout is shown in Figure 3, and the oil heater is shown in Figure 4.
• 6.6 Return oil hole: refers to the small hole on the compound transmission through which the oil passes when returning after flowing through the heat exchanger; its position and size are shown in Figure 5.
• 6.7 Air pressure controller: transmission shifting is achieved by applying air pressure to the shift piston to push the piston; the air pressure is controlled by a solenoid valve, and the opening and closing rate of the solenoid valve is 5 cycles per minute; the number of cycles is recorded by a counter; the air supply and control system are shown in Figure 6.
• 6.8 Instruments and meters: sensors and displays can monitor the following parameters: 6.8.1 test oil temperature; 6.8.2 countershaft speed; 6.8.3 drive shaft speed; 6.8.4 air pressure (system pressure); 6.8.5 air pressure (dynamic change during shifting); 6.8.6 coasting time.
• 6.9 Thermocouple positions: two measurement points. First, a thermocouple is installed in a hole drilled at the bottom of the main transmission housing along the centerline forward 203 mm, and the thermocouple is inserted into the test oil to a depth of 38 mm to measure the transmission oil sump temperature; second, a thermocouple is installed at the heater outlet to measure the test oil temperature in the heater. The installation positions are shown in Figure 7.
• Table 1 Test bench components (name | manufacturer | part number):
  • Display instruments: drive shaft speed (Newport, P-6031D20D); countershaft speed (Newport, P-6031D20D); shift time (Newport, P-6031D20D); coasting time (Newport, P-6031D20D); control display instrument (Newport, original part number requires confirmation against the source standard (source-text extraction)); temperature controller (Fedington, 5EN-Al); temperature indicator (Onmen, INF-0-0-0-0-JF); cycle counter (The-Electric, P2-1006-115AC); cycle timer (Murphy, H5BB-B-AC101-240); T/C selector switch (U.S. Gag, 33112); oil pressure gauge (Norgren, A-20EO, 0-30psi); air supply meter (Asco, P440, 0-160); air regulator (Eleenn, RO-8-300 RNMA); shift solenoid (supplier name unclear in the source, 8317G35, 3-way solenoid); speed sensor (Penn, 3010AN); 12V power supply (Potter & Brumfield, SIS-12-017); air pressure switch (Potter & Brumfield, P61; original part number requires confirmation against the source standard (source-text extraction)); relay-A.C. (Potter & Brumfield, KUP14A15); relay-D.C. (Potter & Brumfield, KUP14A15)
  • Mechanical components: air line (Mack, 101AX24R, 3/8in OD); test oil circulation pump (Browns & Shar, No.2); heater assembly (Chromalox, MOT330A, 220v, 1); test oil line (supplier name unclear in the source, EC-350, No.12); U type universal joint yoke (Mack, 1710 Series, 38MU3413M); drive shaft (RockweU, 1710 Series, 52in collapsed); drive motor (General Electric, 25 Induction Motor, 1760r/min)
  • High-speed recording system: pressure transducer (Sensot, A-5/1034, 0-100psi); oscilloscope (As n., Dash 4)
  • Note: the labels in square brackets "" in Figure 1 are shown in Table 2.
• Table 2 Parts to be removed or installed before the test:
  • Parts to be removed: fence, shift fork, spring and ball on the main transmission shift sleeve [A]; main transmission assembly [B]; main shaft gear and thrust washer; countershaft assembly; sliding clutch; auxiliary transmission [C]; clutch release mechanism; piston and shift fork release mechanism; bell housing [D]; all clutch-related components; shaft; universal joint
  • Parts to be added: speed sensor plug (37KC12) and washer (37AX419); extension pipe connected to the regulator valve, 1/8NPI and shift valve connection hole (63AX3466); replace the cast iron piston cylinder head with a combined steel cylinder head [E]
  • Note: the letters in square brackets "" in Table 2 indicate positions in Figure 1.

6. Recommended operating conditions

• Table 6 Test conditions:
  • Drive shaft speed: 750 r/min ± 10 r/min
  • Cycle rate: 6 s ± 0.3 s (high speed); 6 s ± 0.3 s (low speed)
  • Air pressure: 621 kPa ± 4 kPa
  • Test oil temperature: 121℃ ± 2.7℃
• 11.2.1 Set the air pressure to 621 kPa. Start the drive motor to bring the drive shaft speed to 750 r/min, while the transmission runs at low speed. Turn on the test oil heater.
• 11.2.2 The transmission runs in low gear without shifting, and the test oil is preheated; the test oil is heated until the test oil temperature rises to 121℃±2.7℃.
• 11.2.3 When the test oil temperature reaches the operating temperature 121℃±2.7℃, the test machine automatically starts the shift cycler, and the test begins timing.
• 6.5 Total volume of the test oil circulation system 19.9 L; heating temperature 121℃±2.7℃ (250°F±5°F).
• 6.7 Solenoid valve opening and closing rate per minute 5 cycles.

7. Sampling and specimen preparation

• 9.1 Parts cleaning:
  • 9.1.1 Transmission cleaning: Thoroughly clean the transmission with kerosene to remove residual test oil, sludge, varnish, deposits, etc. from the previous test, and blow dry.
  • 9.1.2 Gear, shaft, synchronizer cleaning: Clean the test components with aviation washing gasoline to remove sludge, varnish, deposits, etc., and blow dry.
  • 9.1.3 Heater, test oil circulation system cleaning: Clean the test oil circulation system with kerosene; after each test, disassemble and clean the heater and blow dry. Periodically check for leakage and repair promptly if necessary.
• 9.2 Assembly:
  • 9.2.1 Commonly used test parts: Assemble the test transmission according to the instructions in the Mack transmission service manual 72130/2180 (unless the test method specifies changes to certain parts). During assembly, lubricate all components with test oil. The parts used in the test are listed in Table 3. For all tests, only the part specifications listed in Table 3 may be used.
  • Table 3 Parts and numbers used in the test (part name | specification 1 part number | specification 2 part number):
    • Synchronizer assembly: 320KB450C | 320KB459
    • Synchronizer pin: 301KC240B | 301KC33
    • Synchronizer pin: 301KC241B | 301KC34
    • Synchronizer pin: 48AX17 | 301KC35
    • Synchronizer spring: 107KD244 | 107KD247
    • High-speed main shaft gear: 751KB489 | 751KB4123
    • Low-speed main shaft gear: 84KC42 | 94KC47
    • Transmission main shaft: 601KG429 (original specification 1 part number requires confirmation against the source standard (source-text extraction)) | 601KG429
    • Transmission main shaft bearing: not required | 46AX538
    • Main shaft thrust washer: 223KD316A | not required
    • Thrust retaining ring: 97AX151 | 97AX151
    • Thrust retaining ring: 97AX267 | 97AX267
    • Shift push rod: 591KC3154A | 591KC3154A
    • Type O washer: 56AX560 | 56AX560
    • Shift piston: 336KC318 | 336KC318
    • Piston chamber: 55KC46A | 55KC46A
    • Type O washer: not required | not required
    • Type O washer: 56AX588 | 56AX588
    • Countershaft gear, front: 757KB3322 | 757KB3322; 757KB4109 | 757KB4108
    • Countershaft gear, rear: 757KB4106 | 757KB4106; 757KB440A (original correspondence requires confirmation against the source standard (source-text extraction))
    • Shift valve: 216KD123 | 216KD42
  • 9.2.2 Test parts:
    • 9.2.2.1 Replace the following new test parts for each test (see Table 4).
    • 9.2.2.2 After each test, inspect the following parts (see Table 5); replace promptly if wear or damage occurs (after each test).
    • Table 4 New test parts used for each test (name | quantity required | part number): assembly (the components in the assembly are listed in Appendix A.1) | 1 | 377SH21; friction disc | 8 | N/A; shift fork | 1 | 575KB457; low-speed main shaft gear | 1 | 84KC47
    • Table 5 Parts required to be inspected after each test (name | quantity required | part number): thrust washer | 3 | 223KD249; thrust washer | 2 | 223KD316A; clutch cover | 1 | 53KG486; high-speed main shaft gear | 1 | 751KB4123
  • 9.2.3 Air valve inspection: Inspect the shift valve plunger and shift cylinder; replace if worn or damaged.
  • 9.2.4 Pre-test measurements: Before each test, measure the hardness and thickness of the friction discs, guide discs, and shift forks.
    • 9.2.4.1 Measurement of friction discs and guide discs: Number each friction disc and guide disc, divide the circumference into three equal parts, and mark them. Measure the thickness at the marked positions and record (see Appendix Table C.1).
    • 9.2.4.2 Shift fork measurement: Divide the friction blocks at both ends of the shift fork into upper, middle, and lower positions, measure the thickness of the shift fork, and record (see Appendix Table C.2). Take the midpoint of the shift fork friction block, measure its hardness on both sides of the friction block; the hardness values at the four measurement points shall not be less than 55HRC (see Appendix Figure C.1).
  • 9.2.5 Countershaft bearing preload measurement: Before each test, measure the preload of each countershaft bearing according to the following steps.
    • 9.2.5.1 Assemble the transmission according to the MACK transmission service manual 72130/2180, including installing the universal joint at the output end of the output shaft. Rotate the transmission so that the main shaft is perpendicular to the horizontal plane.
    • 9.2.5.2 Remove the bearing cap from the shaft end of the first countershaft to be inspected, and measure a shim with a thickness of 0.254 mm (0.010 in). Install this shim together with the shim on the bearing cap onto the bearing cap, and tighten the bearing cap retaining screws. The tightening torque is 54 N·m～68 N·m (40 ft·lb～50 ft·lb).
    • 9.2.5.3 Install a dial indicator on the transmission housing and adjust the probe to measure the axial play of the countershaft.
    • 9.2.5.4 Use a pry bar to move the countershaft to the top dead center; after releasing, record the axial play value. Repeat the measurement at least three times to ensure consistent measurement values.
    • 9.2.5.5 The test requires the countershaft bearing preload value to be between 0.051 mm～0.152 mm (0.002 in～0.006 in). If this requirement is not met, adjust by adding or removing bearing cap shims.
    • 9.2.5.6 Repeat the above steps for the remaining two countershafts. Record the measured values in the table shown in Appendix Table C.3 or an equivalent table.
  • 9.2.6 Transmission torque measurement: Rotate the transmission to a horizontal position, place the transmission in low gear, use a torque wrench to turn the output shaft end lock nut, and measure the starting and rotating torque. Measure three times, and record the average values of the starting torque and rotating torque (see Appendix Table C.3).
  • 9.2.7 Transmission coast-down time measurement: Install the drive shaft, and before installing the top cover, measure the time for the countershaft speed to decrease from 1500 r/min to 500 r/min.
    • 9.2.7.1 Shift the transmission to low gear, and use an oil gun to spray approximately 15 mL of the test oil at each main shaft, drive shaft, and six countershaft bearings.
    • 9.2.7.2 Turn on the drive motor to bring the countershaft speed to 1750 r/min, turn off the motor, allow the transmission speed to decrease to 500 r/min, and record the time for the countershaft speed to decrease from 1500 r/min to 500 r/min, with an accuracy of 0.01 s. Repeat the measurement 5 times. Record the last 5 readings and report their average value (see Appendix Table C.3).

8. Analysis procedure

• 10 Calibration and verification of test equipment:
  • 10.1 Test bench calibration: Calibrate the test bench through reference oil tests for the following purposes: 10.1.1 verify the relevant operations of the standardized test bench; 10.1.2 verify the severity of the test bench; 10.1.3 determine the pass criteria of the test bench.
  • 10.2 Reference oils: Two reference oils are used, namely the pass reference oil (high-quality oil) and the fail reference oil (low-quality oil).
  • 10.3 Reference oil test cycle: After every ten tests completed on the test bench, pass reference oil and fail reference oil tests shall be conducted. For a new test bench, five pass reference oil tests and two fail reference oil tests are required.
  • 10.4 Instrument verification: Before each test, the following instruments shall be calibrated; the instruments shall be inspected according to the instrument manufacturer's instructions and calibration methods. During instrument calibration, the measurement range required by the test method shall be selected as the reference standard, and its deviation shall be less than the allowable measurement deviation required in the test method. Calibration results shall be retained for at least 24 months. 10.4.1 Drive shaft and countershaft speed measurement system; 10.4.2 Temperature sensor and measurement system; 10.4.3 Pressure sensor and measurement system; 10.4.4 Shift time measurement system.
• 11 Test procedure:
  • 11.1 Cleaning of the test machine:
    • 11.1.1 Add 19.9 L of test oil to the transmission system. Turn on the test oil pump to circulate the test oil through the entire system. If the test oil is a non-reference oil, first determine the acceptable results of the test oil based on the reference oil test results. Then use the same test specimens as for the reference oil for the test.
    • 11.1.2 Turn off the test oil heater and allow the test oil to circulate in the system for at least 10 min.
    • 11.1.3 Open the drain valves under the transmission and heater to drain the cleaning oil, which takes about 10 min.
    • 11.1.4 Close the drain valves, add 19.9 L of test oil, install the transmission top cover, and prepare for the formal test.
  • 11.2 Test program:
    • 11.2.1 Set the air pressure to 621 kPa. Turn on the drive motor to bring the drive shaft speed to 750 r/min, while the transmission operates in low speed. Turn on the test oil heater.
    • 11.2.2 The transmission operates in low gear without shifting, and the test oil is preheated; heat the test oil to raise the test oil temperature to 121℃±2.7℃.
    • 11.2.3 When the test oil temperature reaches the operating temperature 121℃±2.7℃, the test machine will automatically start the shift cycler, the test timing begins, and the test operates under the following conditions (see Table 6).
    • 11.2.4 Test data recording is shown in Appendix Table C.4; 1 h shall record the required test parameters once.
    • 11.2.5 Use a recorder and pressure sensor to record the air pressure and intermediate shaft speed during gear shifting. In the following cycle stages, record the test parameters during at least one process of switching from high speed to low speed and from low speed to high speed: 30±20, 25000±300, 50000±300, 60000±300 cycles, and at least record the test parameters at the 5000±200 cycles before five times the average failure cycle number of the reference oil test.
    • 11.2.6 Check these recorded values to ensure that the shift valve and cylinder are working properly.
  • 11.3 Shutdown procedure:
    • 11.3.1 After two nonsynchronous shifts occur in the transmission, the test ends. Nonsynchronous shifting will cause the synchronizer gears to collide, thereby producing a harsh noise (exceeding 114 dB).
    • 11.3.2 Record the final operating conditions, turn off the test oil heater and drive motor, and the test ends.
    • 11.3.3 Drain and collect the waste oil after the 1000 mL test, and drain the waste oil from the transmission and heater.
  • 11.4 Evaluation of the test piece: Disassemble the transmission according to the MACK service manual, inspect the test piece for abnormal wear or damage, and measure the friction discs, guide discs, and shift forks. Use the record forms shown in attached Table C.1 and attached Table C.2 or an equivalent format to record the wear measurement values and the visual appearance of the friction surfaces.

9. Qualitative and Quantitative and Calculation Formulas

• 12 Determine the test results:
  • 12.1 Pass and fail criteria: The number of shift cycles when the synchronizer fails is the evaluation criterion for lubricant performance. The test result is the number of cycles when two nonsynchronous shifts occur in the synchronizer. The pass and fail criteria for the test oil are determined by the requirements of the test specification.
  • 12.2 Fork wear: Measure the transmission fork wear and report this result after the test ends (see attached Table C.2).
  • 12.3 Test validity: Calculate the test validity according to Appendix C. If the percentage deviation of the test operating parameters, the downtime during the test, and the average cycle time are all within the required ranges in Appendix C, the test operation is judged valid.
• Appendix B Test validity and deviation ranges:
  • B.1.1 Downtime: B.1.1.1 Heating stage — there are no requirements for the number and time of shutdowns; B.1.1.2 Test stage (regardless of test length): (a) Shutdowns not exceeding 15 min—— are not counted in the number of shutdowns, but must be reported; (b) The number of shutdowns exceeding 15 min shall not exceed three times; (c) The total downtime shall not exceed 16 h.
  • B.1.2 Test condition deviation: B.1.2.1 To ensure the validity of the test, the deviation of key operating parameters should be strictly controlled: test oil temperature 2.0%; shift air pressure 2.0%; drive shaft speed 5.0%.
  • B.1.2.2 Calculation method for percentage deviation of operating parameters: Formula (B.1), where: △i— value exceeding the standard deviation range; △t— operating time of the test parameter exceeding the standard deviation; s— standard deviation of the test parameter; t— total test time.
  • B.1.2.3 The deviation of key test operating parameters shall not exceed the following ranges: test oil temperature 2.0%; shift air pressure 2.0%; drive shaft speed 5.0%.
  • B.1.2.4 Assume an example as follows: total test time 200 h; test oil temperature (250℉±5℉):259℉ 1h; test oil temperature (250℉±5℉):244℉ 6h; shift air pressure (90psi±2psi):93psi 2h; drive shaft speed (750r/min±10r/min) readings did not exceed the specified range.
  • B.1.2.5 Test oil temperature calculation: Formula (B.2), result 1.0%.
  • B.1.2.6 Air pressure calculation: Formula (B.3), result 0.50%.
  • B.1.3 Average cycle time: B.1.3.1 A test in which the average time of one test cycle is between 12.5±0.65 is judged valid. Formula (B.4), where: t— average time of each cycle; n— total number of test cycles; t— total test time. B.1.3.2 One shift cycle time — refers to the time used to complete one complete shift from low speed to high speed and back to low speed, generally 12.5 s (original numerical value requires confirmation against the source standard (source-text extraction)).

10. Precision

• 14.1 Precision: Determine the reliability of the test results according to the following provisions (95% confidence level).
  • 14.1.1 Test precision is based on five passing oil tests completed on four test benches. Different test benches have different precision. The research report provides the raw data used for calculating test precision.
  • 14.1.2 Table 7 lists the precision test results of five passing reference oil tests and two failing reference oil tests conducted on four test benches. The latest precision data can be obtained from ASTM TMC.
• 14.2 Bias:
  • 14.2.1 In the same laboratory, using the same batch of synchronizer components and two passing reference oils to determine the failure cycle number of the synchronizer. The bias rate of the average value of the most recent five test results of the passing reference oil completed on each bench in the laboratory is about ±19%.
  • 14.2.2 The bias of the average value of ten test results of the passing reference oil completed in different laboratories is about 16000 cycles. Because the reference oil data come from only two laboratories, the reproducibility pattern of this test method cannot be determined.
  • 14.2.3 This test procedure does not calculate bias; it only determines the number of shifts in the test.
• Table 7 Reference oil precision test results (1993 year 4 month):
  • Passing reference oil (5 tests):
    • Test bench A: 62978, 68675, 64709, 74618, 85703; average cycle failure number 71301; standard deviation/s 9234; bias rate/% 13.0
    • Test bench B: 62560, 82255, 69959, 65132, 66837; average cycle failure number 69349; standard deviation/s 7699; bias rate/% 11.1
    • Test bench C: 77696, 86207, 99140, 72336, 87213; average cycle failure number 84518; standard deviation/s 10233; bias rate/% 12.1
    • Test bench D: 68419, 99142, 97824, 79471, 98557; average cycle failure number 88682; standard deviation/s 14017; bias rate/% 15.8
    • Combined value of four benches: 78463; standard deviation/s 10556; bias rate/% 13.0
  • Failing reference oil (2 tests):
    • Test bench A: 23530, 23566, 21880, 25104, 33260, 29239, 27325, 33638, 23548, 23442, 31249, 30482 (original data arrangement requires confirmation against the source standard (source-text extraction))

11. Report

• 13.1 The format required for the test report is given in Appendix D.
• 13.2 Different report formats are also permitted as long as the reported content is the same.
• Appendix D (informative appendix) Test report format:
  • Manual transmission fluid thermal stability evaluation method test result report (cyclic durability test method): test oil name, commissioning unit, test number, test date.
  • Table D.1 Manual transmission fluid thermal stability test result report: test bench number, test number, test start date, test end date, test oil number, test result, test validity, number of test cycles, conclusion, scorer, project leader, center director.
  • Table D.2 Test conditions: test running time, heating time; items (drive shaft speed/(r/min), test oil temperature/℃, shift gas pressure/kPa) minimum value, maximum value, average value.
  • Table D.3 Measurement of test pieces: pre-test preload measurement (intermediate shaft bearing preload 0.051 mm～0.152 mm; torque/(N·m) 1A, 2A, 3A, start, rotate); shift fork measurement (fork number, left, right, friction block hardness (before test)/HRC, friction block measured thickness (before test)/mm, friction block measured thickness (after test)/mm, total wear/mm, average wear/mm); transmission friction disc thickness and wear measurement (No. 1-4, No. 5-8: guide disc + friction disc: before test/mm, after test/mm, wear/mm).
  • Table D.4 Downtime and explanation: laboratory, test bench number, test oil number, test number, number of shutdowns, test time, test date, downtime, shutdown reason, total downtime.
  • Table D.5 Shift curve chart: laboratory, test bench number, test oil number, test number.
  • Table D.6 Shift time curve chart: laboratory, test bench number, test oil number, test number.

12. Referenced Documents

• GB 253 Kerosene
• SH 0114 Aviation washing gasoline
• Note: For dated referenced documents, all subsequent amendments (excluding errata) or revisions are not applicable to this standard. However, parties reaching agreements based on this standard are encouraged to study whether the latest versions of these documents can be used. For undated referenced documents, the latest version applies to this standard.

13. Source and verification

This page is an AI translation of the available Chinese method card. Human verification is pending. It is not an official translation of the standard. Check the source standard and product certificate before use.

14. Quick Q&A Reference