Locking Hubs - Automatic GMC Pickup R1500

DESCRIPTION

The automatic locking hub automatically engages to lock and disengages to unlock the front axle shaft to (or from) the front hub. Shifting the transfer case into 4WD immediately engages automatic locking hubs. Hubs remain engaged even during coasting or downhill operation. Automatic locking hubs disengage when the transfer case is shifted into 2WD, and when vehicle is slowly moved rearward several feet.

Removal

1. Remove 5 cap screws and cover to outer clutch housing. Remove bearing race spring assembly. Remove sealing ring and seal bridge retainer. Remove bearing components.
2. Squeeze tangs of wire retaining ring together with needle nose pliers. Pull remaining components of automatic hub from wheel. (Scheme 1)

Scheme 1

1. Make sure lock ring is in position between wheel bearing adjusting nut and adjusting nut. Using Bearing Nut Wrench (J-6893-D), tighten wheel bearing adjusting nut to 50 ft. lbs. (60 N.m) to seat bearings.
2. Back off nut and tighten to 35 ft. lbs. (47 N.m) while rotating hub. Finally, back off nut a maximum of 3/8 turn. Assemble lock ring (with tab in keyway) over axle shaft, against bearing adjustment nut.
3. Adjustment nut pin must pass through one of the washer holes. Tighten outer adjusting nut to 183 ft. lbs. (248 N.m). Align outer clutch housing splines with splines of wheel hub.
4. Loosen cover screws 3 or 4 turns, and push in on cover to allow retaining ring to expand into rotor hub groove. Tighten cove cap screws to 40-50 INCH lbs. (4.5-5.6 N.m).

Rebuilt Hub

1. Hold 2 tangs of retaining ring clamped while installing components in hub. Align drag sleeve cut-outs with lock ring tabs while assembling splines of outer clutch housing into hub splines.
2. Assemble seal bridge retainer (K10/20 models) or assembly aid retainer (K30 models) in outer clutch housing cut-out. On K10/20 models, assemble sealing ring over outer clutch housing.
3. Assemble bearing and retainer into hub sleeve. Assemble bearing race spring to cover.

Scheme 2

1. Remove snap ring from hub sleeve groove. Turn clutch gear until it engages with outer clutch housing. Lift and cock drag sleeve to unlock brake band tangs from inner cage window. Remove drag sleeve and the brake assembly. NOTE: Brake band should never be removed from drag sleeve. Brake band spring tension can be changed if coils are overexpanded.
2. Remove snap ring from outer clutch housing groove. Using a small screwdriver, while removing inner cage, pry plastic outer cage from inner cage. Pry plastic outer cage tabs from groove in outer clutch housing. Remove outer cage.
3. Remove clutch sleeve and attached components from outer clutch housing. Compress and hold return spring with fabricated clamps. (Scheme 2) After installing clamps, put assembly in vise so vise holds both ends of clutch sleeve.
4. Remove retaining ring. Remove clamps holding return spring. Slowly open vise. Remove retainer seat, spring and spring support washers from hub sleeve.
5. Remove "C" retaining ring from clutch sleeve by positioning assembly so "C" ring ends align with cam follower legs and removing "C" ring through follower legs.
6. Remove conical spring from between cam follower and clutch gear. Separate cam follower from clutch gear.

CLEANING & INSPECTION

Wash all parts with cleaning solvent and blow them dry. Check cover for cracks or pitting condition. Replace any components that are worn or damaged. Dip all parts except bearing and race assembly, brake band, and drag sleeve assembly in ATF.

REASSEMBLY

1. Snap cam follower tangs over clutch gear flats. Compress conical spring and slide it into position with large end of spring against clutch gear.
2. Position clutch gear assembly over hub sleeve splines. Cam follower teeth should be on hub sleeve end that has no splines. Clutch gear and spring should slide freely over hub sleeve splines.
3. Assemble "C" retainer ring in hub sleeve groove. Assemble spring retainer over each end of return spring. Position one end of return spring with retainer against shoulder of clutch gear.
4. Place spring support washer against retainer on return spring end. Compress return spring and assemble retainer ring in hub sleeve groove. Retain return spring using 2 fabricated clamps, while retainer ring is being assembled. (Scheme 2)
5. Place assembled components in outer housing. Position cam follower so 2 legs face outward. Install 3 cover screws into outer clutch housing for support and to permit clutch hub to drop down.
6. Carefully work plastic outer cage into outer clutch housing with ramps facing cam follower. External tabs of plastic cage should be in wide groove of outer clutch housing.
7. Assemble steel inner cage into outer cage, aligning outer cage tab with inner cage window. Assemble retaining ring into outer clutch housing, above outer cage. NOTE: Service brake band and drag sleeve as an assembly. If original lubricant has been removed or contaminated, use 1052750) lubricant.
8. Assemble one of 2 tangs of brake band on each side of outer cage lug, located in window of steel inner cage. Remove 3 cover screws and set end of hub sleeve on a support. Assemble washer and snap ring above drag sleeve. To complete installation, install rebuilt hub as previously described in this article.