Pinion Gear Adjustment
Correct running position is determined by moving the pinion in an axial direction. Then the ring gear is lifted out of the no-play meshing position so backlash will be kept within specified tolerances. Deviation "r" is the adjusting distance called for by design (design distance "R"). This is measured and recorded on face of drive pinion. Ring and pinion gears are supplied so deviation "r" is always added to "R" and is proceeded by a "+" sign. See Fig 1.
- When adjusting pinion and ring gear, the following sequence should be used:
- Determine the total shim thickness ("S1" + "S2") for the specified preload of the tapered roller bearing differential.
- Determine shim thickness ("S3").
- Divide total shim thickness in "S1" and "S2" to provide correct backlash between the pinion and ring gear.
- The adjustment distance "E" is calculated from known design distance "R" = 2.941" (74.70 mm) + deviation "r".
- With pinion bearing adjusted and pinion nut tightened to proper specifications, install final drive housing (without shims) to transmission and tighten all nuts to specifications. Install one side cover (without "O" ring) and secure with 2 bolts.
- Set adjusting ring of Master Gauge (VW 385/1) at 1.61" (41 mm). Install Centering Discs (VW 385/4) on master gauge and attach Plunger (VW 385/14) with dial indicator extension. See Fig 2.
- Install measuring gauge in case, install second side cover (without "O" ring) and secure with 2 bolts. Set dial indicator to distance "E" + .20" (5 mm). Install Measuring Bar (VW 385/1) and set at zero with .004" (1 mm) preload.
- Turn measuring bar until dial gauge extension is vertical to face of pinion head. At this time, dial gauge needle will reach its highest point and dial gauge should be read. Install determined shim thickness ("S3") between the transmission case and final drive housing. Recheck distance after installation of shims. A tolerance of ± .0006" (.015 mm) is allowed.