Drive Pinion Installation & Adjustment

PINION DEPTH, ADJUST
Correct pinion depth must be established to ensure proper ring gear and pinion tooth contact. Pinion depth is adjusted by varying thickness of shims installed either between rear pinion bearing and gear, or between rear pinion bearing race and housing. If original ring gear and pinion, rear pinion bearing and housing are to be reused, original shims removed during disassembly can be used to adjust pinion depth. However, if gear set, rear pinion bearing assembly or housing are replaced, proper pinion depth must be adjusted using following procedures.

Fig. 15 Pinion depth gauge assembly. Models w/8-3/8 inch ring gear:

MODELS W/8-3/8 INCH RING GEAR
Pinion setting gauge assembly C-3715-B and adapter set C-4339 or suitable equivalents must be used to select pinion depth adjusting shim and install pinion bearing races. Depth adjusting shims are installed between rear pinion bearing race and housing on 1980---83 models or between rear pinion bearing and gear on 1984---87 models.
1. Start both pinion bearing races in respective housing bores, ensuring that races are not cocked, then lubricate pinion bearings and races.
2. Assemble spacer SP-6030 on shaft SP-5385 followed by rear pinion bearing, then insert assembly into housing from case side.
3. Hold assembly in case, mount front bearing on spacer SP-5382 and install spacer and bearing assembly, then washer SP-6022, sleeve SP-3194-B, centering washer SP-534 and nut SP-3193 onto shaft.

Fig. 16 Typical pinion bearing race installation:

Fig. 17 Pinion depth adjusting shim selection:

4. Hold compression sleeve with suitable tool, then tighten nut to draw bearing races into housing rotating shaft to prevent damage to bearings.
5. When bearing races are fully seated, loosen nut, then retighten in small increments to obtain 10---25 inch lbs. preload, checking preload with suitable torque wrench after each adjustment. Ensure that bearing rollers are lubricated to ensure accurate reading.
6. Rotate tool to ensure that bearings are properly seated, recheck preload and adjust as needed.
7. Mount gauge block SP-5383 onto head of shaft and securely tighten allen screw.
8. Mount arbor SP-6029 in housing side bearing bores, ensuring that arbor is centered.
9. Install side bearing caps in proper position, insert 0.002 inch shim stock between each bearing cap and arbor, and torque bearing cap bolts to 10 ft. lbs.
10. Insert progressively thicker shims between arbor and gauge block, until fit of shim is snug but not excessively tight, then record thickness of shim.
11. Inspect head of pinion for pinion depth modification code and select shim as follows: To ensure proper tooth contact, pinion may be marked with a plus (+) or minus ( - ) code number, indicating in thousandths of an inch necessary modifications to the "nominal" depth setting. It is essential that this modification code be factored when selecting pinion depth adjusting shim.
a. If pinion is marked with a minus ( - ) code, add that number of thousandths to dimension obtained in step 10, and select shim thickness equal to sum.
b. If pinion is marked with a plus (+) code, subtract that number of thousandths from dimension obtained in step 10 and select shim thickness equal to remainder.
12. Remove gauge tool and adapter assemblies from housing and pinion bearings from shaft.
13. On 1980---83 models, remove rear pinion bearing race from housing using brass drift, install selected pinion depth adjusting shim into housing, then reinstall bearing race as outlined in steps 1 through 5.
14. On 1984---87 models, retain selected shim for pinion installation.

Fig. 16 Typical pinion bearing race installation:

Fig. 18 Pinion depth gauge assembly. Models w/9-1/4 inch ring gear:

MODELS W/91/4 INCH RING GEAR
Pinion setting gauge assembly shown or suitable equivalent may be used to install pinion bearing races and to select proper shim thickness for pinion depth adjustment. Pinion depth shims are installed between rear pinion bearing and gear.
1. Start both pinion bearing races into housing, ensuring that races are not cocked, then lubricate pinion bearings and races.
2. Assemble spacer SP-6017 then the rear pinion bearing on shaft SP-526 then insert shaft assembly into housing from case side.
3. Install front pinion bearing, washer SP-6022, compression sleeve SP-535-A centering washer SP-534 and nut SP-533 on shaft.
4. Hold compression sleeve with suitable tool, then tighten nut to draw bearing races into housing rotating tool to prevent damage to bearings.
5. When bearing races are seated, loosen nut on tool until endplay is evident, then lubricate bearings.
6. Hold compression sleeve and tighten nut in small increments to obtain bearing preload of 15---25 inch lbs., checking preload with suitable torque wrench after each adjustment.
7. Rotate tool to ensure that bearings are seated, recheck preload and adjust as needed.
8. Mount gauge block SP-6020 onto head of shaft SP-526 install screw SP-536 and securely tighten screw.
9. Install arbor SP-6018 in housing side bearing bores and center arbor.
10. Install side bearing caps in respective position, insert 0.002 inch shim stock between each cap and arbor, then torque cap bolts to 10 ft. lbs.
11. Insert progressively thicker shims between arbor and gauge block, until fit of shim is snug but not excessively tight, then record shim thickness.
12. Inspect head of pinion for pinion depth modification code and select depth adjusting shim as follows. To ensure proper tooth contact, pinion may be marked with a plus (+) or minus ( - ) code number, indicating in thousandths of an inch necessary modifications to the "nominal" depth setting. It is essential that this modification code be factored when selecting pinion depth adjusting shim.
a. If pinion is marked with a minus ( - ) code, add that number of thousandths to dimension obtained in step 11 and select shim thickness equal to sum.
b. If pinion is marked with a plus (+) code, subtract that number of thousandths from dimension obtained in step 11 and select shim thickness equal to remainder.
13. Remove gauging tool assembly from housing and bearings from tool.

Fig. 19 Companion flange & front pinion bearing installation:

DRIVE PINION, INSTALL
1. Install bearing races, and bearing race shims if equipped, in housing as outlined in "Pinion Depth, Adjust."
2. On models with 91/4 inch ring gear and 1984---87 models with 83/8 inch ring gear, install selected depth adjusting shim on pinion.
3. On all models, press rear bearing onto pinion using suitable spacer to ensure that bearing is fully seated.
4. Install new collapsible spacer on pinion, lubricate pinion bearings, then insert pinion assembly into housing.
5. Install front pinion bearing, companion flange and forcing tool on pinion. Use tool C-3718 on models 3/8 inch ring gear, C-496 on models with 91/4 inch ring with 8 gear or suitable equivalents.
6. Hold companion flange and tighten nut on forcing tool to seat front bearing on pinion shaft. Care must be taken not to collapse spacer when seating front bearing on pinion shaft. Tighten tool only until endplay has been eliminated.
7. Remove forcing tool and companion flange, then install new pinion seal using suitable driver.
8. Lubricate lips of pinion seal, then reinstall companion flange using forcing tool as outlined in steps 5 and 6.
9. Remove forcing screw, then install washer and new pinion nut.

Fig. 8 Measuring pinion rotating torque (bearing preload):

10. Hold companion flange and torque pinion nut to 210 ft. lbs., then check bearing preload using suitable torque wrench. Bearing preload must be within specifications with pinion nut torqued to a minimum of 210 ft. lbs. If bearing preload is greater than specified at minimum torque specification, or if preload is not even through full rotation, recheck pinion installation, replace collapsible spacer and repeat adjustment.
11. If bearing preload is less than specified, continue tightening nut in small increments, checking preload after each adjustment. If specified preload is exceeded, spacer will be collapsed too far to be reused. Spacer must be replaced and adjustment procedure must be repeated. Do not loosen pinion nut to reduce preload.