Operation CHARM: Car repair manuals for everyone.

Cam Gear Shim Selection

If cam gear is replaced, or if original cam gear shim thickness cannot be determined, shim must be selected to maintain proper backlash with differential pinions using following procedure.
1. Install 6 guide clips on cam gear clutch ears, then insert cam gear assembly into right case half.

Fig. 5 Cam/side gear installation for assembly clearance measurement. Eaton locking differential:






2. Clamp cam gear assembly securely in case pocket using suitable bolt, nut and washers as shown in Fig. 5.
3. Install all 3 differential pinions and thrust washers on yoke and firmly seat pinion and yoke assembly in case, tapping assembly with suitable hammer.
4. Slightly loosen bolt clamping cam gear into case and index one pinion gear tooth so that it points downward, perpendicular to parting line of case, then retighten cam gear clamping bolt.
5. Mount suitable dial indicator on case with plunger contact bearing against tooth indexed in step 4.






6. Firmly hold pinion into seat, rock pinion back and forth against cam gear and record backlash reading from dial indicator, Fig. 6.
7. Repeat steps 4 through 6 with each remaining pinion, then select cam gear shim that will provide .010-.018 inch backlash between all pinions and cam gear. When cam gear and/or shim is replaced, thrust blocks must be measured and selected to maintain proper clearance during assembly.