To check the pinion preload...
To check the pinion preload measurement, assemble the shim pack, front bearing, and yoke onto the pinion, and torque the retaining nut to 200 ft-lb for 28-spline and 250 ft-lb for 35-spline. Lightly oil the bearings and measure the preload using an inch-pound dial wrench. The preload needs to be 25 in-lb. If the preload is too high, add shims; if it's too low, subtract shims to achieve the correct measurement.
Carefully disassemble the...
Carefully disassemble the pinion support and install the oil seal. After that, you can perform the final assembly of the pinion support and install the pinion nut to the specified torque using red Loctite. Use a light coating of assembly oil on the seal to prevent damage during the first few miles of use.
Flip the differential case...
Flip the differential case over and remove the bearing caps, adjusters, and adjuster lock tabs, making sure you mark or label the hardware to return it to its original location. We're using the Strange S-series nodular-iron differential, which features radial ribs for strength, extra thick main caps secured by Allen-head main cap bolts, and steel adjuster nuts. The differential is lowered into place and the adjuster nuts (with a coating of antiseize), main bearings, and Allen-head main cap bolts are installed. The Allen-head main cap bolts need to be tightened to 85 ft-lb for this iron case.
Even though we're working...
Even though we're working with a complete buildup from scratch, for those following along with their own 9-inch rebuild, we recommend replacing all of the bearings. Here the tail bearing for the pinion is pressed into the differential case using a bearing installer (to only press on the outer edge of the bearing); then the bearing retainer, installed with the teeth facing up, is hammered into place until seated on the bearing itself.
The pre-finished pinion support...
The pre-finished pinion support can now be married to the differential case. The Strange tech began by slipping a 0.017-inch-thick shim (as a starting point for setup) into place and then securing the pinion support with the five pinion support bolts. The pinion support is not symmetrical and will only bolt in one way. The bolts are tightened to 45 ft-lb.
As a starting point, Strange...
As a starting point, Strange sets its backlash by tightening the driver-side adjuster until there is zero backlash between the ring and pinion gear, and then adjusts the backlash via the passenger-side nut, which moves the ring gear away from the pinion, creating backlash, and preloads the carrier bearings. Don't forget to stop the adjusters where you can install the lock tabs.
Now the Strange tech can measure the actual backlash via a dial indicator. He zeros the indicator on the drive side of a gear tooth and then rotates the ring gear without moving the pinion. The backlash must be within 0.008 to 0.012 inch, otherwise you will need to rotate the adjusters to get the backlash into spec. Check it at three points around the ring gear and ensure they do not vary by more than 0.004 inch. Once the backlash is set, the gear pattern must be checked with marking compound to ensure the gears will be quiet. The pattern should be centered from heel to toe and from root to top of the teeth. If the pattern is too close to the heel (outside edge of the ring gear), then you need a smaller shim between the pinion support and differential case. If it's too far, you need a thicker shim. Finally, check that the preload is between 45 to 50 in-lb by rotating the pinion nut with a dial wrench attached. If the preload is less than desired, tighten the differential adjuster nuts evenly-and vice versa for too much preload-and the install the adjuster lock tabs and tighten their-head cap screws to 15 ft-lb.
Housing Fabrication
Strange...
Housing Fabrication
Strange fabricates its own housings using a slotted axle-tube mounting configuration for more strength, an exclusive to Strange. This design offers more strength and greater weld contact area, yet looks stock appearing from the rear. Axle tubes are cut to length per the customer's order, which includes track width, brake package, and other pertinent info to ensure a proper fitting housing. The axle housing is set into a fixture, and then the axle tubes are slid into place and fully welded.
After the welds are done,...
After the welds are done, you can see the slotted housing configuration and how much weld goes into the assembly. Though we didn't option it on our 9-inch build, Strange does offer a back brace option for even more strength, something that really helps in drag racing.