Ring Gear, Adjusting

Ring Gear, Adjusting
(Adjusting differential)
It is necessary to readjust ring gear if any of the following have been replaced:
^ Transmission housing
^ Differential cover
^ Differential tapered roller bearing
^ Differential housing
or
^ Gear set
Adjustment overview Overview


Adjusting beveled gear tapered roller bearing preload for final drive

^ Drive pinion removed.
^ Grooved ball bearing, tapered ring and spring removed.
- Install 1.5 mm shim (2 shims of 0.75 mm) in small tapered roller bearing outer race seat (S2 side).





- Press tapered roller bearing outer race into transmission housing
- Install differential into transmission housing.





- Press tapered roller bearing outer race without shim into differential cover.
- Install cover and tighten bolts to 25 Nm (18 ft. lbs.).





- Mount dial indicator and "0" with 1 mm preload.
- Move differential up and down and note play indicated on dial indicator (Example: 0.60 mm)

CAUTION: Do not turn differential when measuring otherwise the bearing will settle giving a false measurement

Determining shim thickness "S1"
The specified bearing preload is obtained by adding a constant figure (0.40 mm) to the reading obtained.





Example:






Friction moment, checking
^ rive pinion removed
A -Commercial torque gauge 0 ... 600 Ncm
For new tapered roller bearings the friction torque must be 70 ... 150 Ncm (6 - 13 inch lbs.).
For used tapered roller bearings the friction torque must be at least 30 Ncm (3 inch lbs.).

Backlash, adjusting
Pinion shaft installed with S3 and S4
- Differential: S_total (S1 + S2) installed in transmission housing.
- Install final drive cover and tighten bolts to 25 Nm (18 ft. lbs.).
- Turn differential several times in both directions so that the tapered roller bearings settle.





- Set up measuring tools.
- Set measuring lever VW 388 to dimension "a" = 70 mm (2.75 inch).
- Turn ring gear to stop. Set dial indicator to zero, turn ring gear back and read backlash. Note reading.





- Position separating device -A- (e.g. Kukko 17/2) if drive pinion turns while turning differential so that an exact backlash can be measured.
- Loosen clamping sleeve locking screw and after turning ring gear through an additional 90°, repeat complete measuring process 3 more times. Add the four measured values together and calculate average backlash.

Calculating average backlash





Example:
Average backlash = 1.96 mm ÷ 4 = 0.49 mm.

Ring gear installation is not correct If the individual measurements differ by more than 0.06 mm, or the ring gear and pinion themselves are damaged. Recheck the installation, and if necessary replace ring gear and pinion.

Shim S2 thickness, determining
- Subtract backlash from the thickness of the inserted shim "S2" multiplied by 1.17 (constant) and add the lift 0.20 (constant).





Example:

- Determine shim according to table.

Shim S1 thickness, determining
S1 = S_total - S2





Example:






Table of shims "S1" and "S2

If a larger shim is required than those listed in the table, install two shims totalling the correct figure.
- Different tolerances make it possible to determine exact thickness of shim(s) required.
- Install determined shims S1 and S2.

Backlash, measuring
- Must be 0.15...0.25 mm.