ASTM D7038 Standard Test Method for Evaluation of Moisture Corrosion Resistance of Automotive Gear Lubricants
9. Preparation of American Axle K2XX Hardware
9.1 When Dana Model 30 hardware is used instead, follow the preparation instructions in Annex A10.
9.1.1 Cleaning of Reused Fittings, Seals, and so forth - Clean, as necessary, all reusable parts including axle tube opening seals, pressure relief system and elbow, and the temperature sensor and its fittings.

9.2 Differential Assembly Build-Up:
9.2.1 Cleaning and Preparation of Parts:
9.2.1.1 Disassembly - Completely disassemble the differential housing assembly, leaving the pinion inner and outer races in place. Remove all parts from the differential case. Disassemble all bearings from their mating parts. Maintain right differential case shim for axle assembly.

9.2.1.2 Differential Housing Modification - Drill and tap the housing to accept the temperature sensor using the template shown in Figs. A5.12 and A5.13. Install the temperature sensor so that the tip of the sensor is 1 in. +/- 0.25 in. (25.4 mm +/- 6.4 mm) from the floor of the differential housing as shown in Fig. A5.4. Tap the housing vent tube opening to 1/4 in. NPT to install the pressure control device.

9.2.1.3 Cleaning - Pressure wash the differential housing and each individual component with solvent (see 7.2) using a round plastic bristle brush. Rinse the differential housing and each individual component with solvent, and dry them with compressed air or nitrogen. Do not use wire brushes or abrasive cleaning pads to clean the differential housing and individual components. Remove all grease and oil used during manufacturer's assembly from bearings and wipe clean lip seals with a dry cloth.

9.2.1.4 Functional Surface and Cover Plate Preparation - Abrasive blast the entire differential case, ring, pinion, side gears, differential pinion gears (spider gears), all four thrust washers and the inside surface of the housing cover plate by uniformly abrasive blasting with 80 grit aluminum oxide. Do not abrasive blast the bearings, bearing cups and differential shaft (cross shaft pin). Do not touch any cleaned surface with bare hands as moisture can cause rusting.
(1) After abrasive blasting and pre-test inspection (see 9.2.1.5), pressure wash abrasive blasted parts, all four bearings, and bearing cups with solvent and a round plastic bristle brush (pressure not to exceed 30 psi (207 kPa) (see 6.1.2). After pressure washing, rinse with solvent and dry with filtered compressed air or nitrogen (pressure not to exceed 30 psi (207 kPa) (see 7.2). A Wilkerson filter, model M18-02-CH00 is required to filter the compressed air or nitrogen. A Wilkerson model MTP-96-64617 is the required replacement element for the filter assembly. Do not use wire brushes or abrasive-cleaning pads to clean the abrasive blasted parts. Do not spin dry the bearings with the compressed air or nitrogen. Only use blowguns without a safety bypass to air-dry the parts. A Milton model S15 has been found to be acceptable.

9.2.1.5 Pre-Test Inspection - After the parts have been abrasive blasted, and before cleaning and rinsing, carefully inspect the abrasive blasted parts, bearings, and bearing cups for rust or corrosion and damage. If any rated area is found to have rust, re-prepare as described in 9.2.1.4. If defects are found, such as casting flaws and so forth, that might be mistaken for rust at the end of test inspection, add a notation of their pre-test existence to the test report. If any bearing is found to have rust or damage, replace it with a new one that is rust-free. The replaced bearing shall be from the same manufacturer and have the same bearing part number. At the end of test inspection and rating make no allowances for parts rusted before start of test.

9.2.1.6 Test Oil Coating - Immediately coat all abrasive blasted parts evenly with test oil after they have been cleaned, rinsed, and dried. Immediately coat all four bearings, bearing cups, and differential shaft (cross shaft pin) evenly with test oil after they have been cleaned and rinsed. (Bearings, bearing cups, and differential shaft (cross shaft pin) are not abrasive blasted). Dipping the parts in test oil or pouring the test oil over the parts are acceptable methods. Do not use brushes to coat the parts with test oil. Do not touch any test parts with bare hands; fingerprints can cause rusting.

9.2.1.7 Lightly coat all bolts with test oil prior to assembly of test axle.

9.2.1.8 Clean, rinse, dry, and coat all parts with test oil within 2 h after abrasive blasting.

9.2.2 Assembly of Test Unit:
9.2.2.1 Drive Pinion Shaft Installation - Assemble the drive pinion shaft with its bearings and install it in the housing following the guidelines in 9.2.2. A late model GM, GMC, or Chevrolet service manual may be used for assembly detail.
(1) Install the rear pinion bearing onto the pinion shaft with the original shim.
(2) Place the front pinion bearing into the housing and then install the pinion front seal into the housing. Note that the front seal might be damaged during disassembly and may need to be replaced.
(3) Install the pinion shaft into the differential housing. The front bearing may need to be tapped into place using a small punch. Install the pinion yoke washer and nut. Torque pinion-nut until a turning torque of 3 lbf-in to 10 lbf-in (0.3 N·m to 1.1 N·m) is achieved.
(4) If necessary, replace the pinion crush collar and repeat pinion assembly process.
(5) Record the final pinion break and turning torque on the appropriate test report form.

9.2.2.2 Differential Case Installation - Assemble the differential pinion, side gears, shafts and thrust washers, shims, and bearings. Install the differential case assembly and bearing caps in the differential housing. Torque the differential housing bearing caps to 35 lbf-ft to 50 lbf-ft (48 N·m to 68 N·m). Measure break and turning torque; turn torque shall be 7 lbf-ft to 13 lbf-in. (0.8 N·m to 1.5 N·m) and break torque shall be 8 lbf-ft to 18 lbf-in. (0.9 N·m to 2.0 N·m).
(1) Adjust the final turning torque by removing the differential case, adding or removing shims on the left ring gear side only, and then reassemble to obtain final preload.

9.2.2.3 Test Oil Addition - Charge 91 oz +/- 2.3 oz (2.7 L +/- 0.07 L) of test oil to the test unit.

9.2.2.4 Cover Plate, Seals, Temperature Probe Installation - Install the cover plate with a new TFE fluorocarbon gasket, pre-wetted with the test oil on both sides (see 6.2.4). Use a new TFE fluorocarbon cover plate gasket for every test. Torque the cover plate bolts to 20 lbf-ft to 25 lbf-ft (27 N·m to 34 N·m). Install the temperature probe using TFE fluorocarbon tape as shown in Fig. A5.4, Fig. A5.12, and Fig. A5.13. Install the NPT stainless steel 90° street ell and stainless steel full port valve.

10. Calibration
10.1 Reference Test Frequency - Conduct one reference test every ten test starts or every five months, whichever comes first. This calibration frequency is subject to change as required. Current calibration information is available from the TMC. (See Annex A2 for general calibration information.) Any test started on or before the stand calibration expiration date is defined to have been run on a calibrated stand.

10.2 All tests are consecutively numbered on a storage box basis. Each storage box has its own unique, permanent identifier. Every test start shall receive a sequential test run number designated before testing begins. All test starts, including aborted starts and operationally invalid tests, shall retain their test run number.

10.3 Consider as non-interpretable any non-reference oil test that has not been run in a calibrated test stand or not conducted on approved hardware, or both. Indicate on the cover page of the test report that the test is non-interpretable and that it has not been conducted in a valid manner in accordance with this test method.

10.4 Instrumentation Calibration:
10.4.1 Prior to every stand calibration attempt, calibrate the drive speed measuring system and the temperature control systems (storage box and motoring stand) against a known standard, traceable to NIST.

10.4.2 Prior to every stand calibration attempt, calibrate the pressure relief system, using the following process:
10.4.2.1 From the bottom of the dip tube, measure 27.75 in. +/- 0.125 in. (704.9 mm +/- 3.18 mm) and mark this distance on the dip tube.

10.4.2.2 Apply 1 psi (6.9 kPa) to the dip tube.

10.4.2.3 Fill the water column reservoir with specified test water, (see 7.1), until 1 psi (6.9 kPa) is displaced.

10.4.2.4 Release the pressure in the dip tube, and mark the static water level on the dip tube.

10.4.2.5 Apply air pressure to the dip tube until air begins to bubble from the tube to verify calibration. Air pressure shall be 1 psi +/- 0.1 psi (6.9 kPa +/- 0.7 kPa).