How do I Install a 373 Ring & Pinion 10-Bolt?
- 1). Raise the rear of the vehicle using the floor jack and place jack stands under the rear axle tubes. Lower the vehicle onto the jack stands. Remove the rear tires using the lug wrench to remove the lugs. Pull the brake drum off each rear brake. Place the drain pan under the transmission rear tail housing.
- 2). Remove the nuts on the U-bolts securing the rear universal joint on the driveshaft to the pinion yoke. Pull the U-bolts out of the pinion yoke. Lower the rear of the driveshaft and pull it out of the transmission tail housing. Remove the large pinion nut in the center of the pinion yoke using an air gun and socket. There is a lot of torque on this nut and it will not come off by hand.
- 3). Pull the yoke off the pinion shaft. Move the drain pan from under the transmission and place it under the rear differential. Remove all the 13 mm bolts in the differential cover using a socket. Remove the differential cover slowly allowing the gear oil to drain into the pan. If it is hard to get off, use a common screwdriver to pry the cover away from the differential.
- 4). Turn the differential carrier by using either axle hub until the center pin in the carrier is angled down to the point it can be removed without hitting the case. Make sure the end of the pin with the through-pin that holds it in place is on the low end of the pin. This is the pin that runs through the center of the carrier and the spider gears. When the small bolt on the bottom is removed, the pin will fall out.
- 5). Remove the pin bolt using a small 1/4-inch wrench. Make sure the pin has just enough room to fall downward and come out with barely enough clearance between it and the case. This is so access to the hole in the center of the carrier is accessible. Once you remove the pin, do not rotate the carrier in either direction -- the pin holds the spider gears in place and with it removed the spider gears are free to move and can fall out. It is a difficult process for a beginner to re-install them and align them with the pinhole.
- 6). Push both axle hubs in as far as they will go. This pushes the axle in toward the center of the carrier, exposing the C-clips that hold the axles into the carrier. Remove the C-clips using a needle nose pliers. Pull the axles half way out of the axle, to ensure they are free of the carrier.
- 7). Reinstall the carrier pin and loosely install the holding pin. Now it is safe to rotate the carrier since the pin is holding the spider gears in position. Remove the two 5/8 bolts in both carrier clamps using an air gun and socket.
- 8). Prepare to remove the carrier from the differential housing. Remember that it is important to keep the spacers on both sides of the carrier bearings separated because they are different sizes, and that the carrier is heavy and can surprise you when it comes loose. Don't drop it on your head. The bearing races will also fall off if you don't stick your fingers through them as the carrier comes out. Grab it with both hands and as it comes out lay it on a clean cloth. It must be kept clean. Keep the bearing races and spacers separated.
- 9). Pull the pinion out from the inside of the differential housing. It may be necessary to tap the pinion shaft to give it some incentive to come out. Pull the crush collar out of the housing behind the pinion if it does not come out with the pinion.
- 10
Take the old and new pinion to a machine shop and have the pinion bearing on the old pinion removed. Save the spacer beneath the bearing. Place the spacer on the new pinion and have the shop install a new pinion bearing on the pinion. The old bearing will be destroyed when it's removed. - 11
Stand the carrier up on the opposite side of the ring gear. Remove the bolts in the ring gear using an air gun and socket. Tap the back, or bolt side, of the ring gear slightly to get it to fall off. - 12
Install the new ring gear by lifting it up and aligning the holes. Insert a few bolts and just start threading them in by hand to ensure alignment. Tighten all the bolts with the air gun and socket in an alternating pattern so it is drawn up evenly. - 13
Install the crush collar on the pinion shaft and install the new pinion from the inside of the differential housing, pushing it in as far as possible. Install the yoke and large pinion nut. Hold the pinion gear on the inside of the differential with one hand and tighten the large pinion nut using the air gun and socket. Tighten it in short bursts while continuously pulling and pushing on the pinion yoke. Stop when the yoke will no longer move in and out. Make sure the pinion rotates smoothly. - 14
Place the bearing races and shims on the ends of the carrier and place the carrier back into the differential. When the carrier fits into the pockets in the differential, it may be necessary to gently tap the shims into place so they are flush with the bearing races. Install the carrier caps and tighten the bolts securely. - 15
Place the dial indicator in such a manner that the dial foot just contacts the teeth on the ring. Move the ring fore and aft and check the freeplay. It should have no more than .004 inch of play in the pinion and ring. If there is, remove the carrier and switch the shims from one side to the other. If it still has too much freeplay use the shims in a shim kit to set the freeplay properly. - 16
Move the carrier so the pin is in place again for removal and do so. Push each axle in as far as they will go. Install the C-clips in the grooves on the ends of the axles, then pull the axles all the way out as far as possible to lock the C-clips in place. - 17
Install the carrier pin and tighten the small securing bolt. Clean all the gasket material off the differential cover. Spread a thin 1/8-inch line of RTV sealant around the outside circumference of the cover. Allow it to set until it begins to skin. - 18
Install the differential cover and tighten all the bolts. Install the brake drums by pushing them on. Install the wheels and tighten all the lug nuts. Install the driveshaft by inserting the front yoke into the transmission tail shaft and pushing it in all the way. - 19
Place the rear universal joint in the pinion yoke, insert the C-clamp bolts around the universal joints and through the yoke and tighten the nuts with a wrench. Remove the filler plug on the side of the differential housing and pour the positraction additive in the hole. Fill the differential the rest of the way with gear oil. It is full when the oil is level with the filler hole. Install the filler plug.