Bearings, pinion seal, depth and carrier shims, crush sleeve and pinion nut for a gear swap in a 1969-1973 Chrysler 8-3/4 with the 489 case.
Putting new gears in a Dodge, Plymouth or Chrysler with the 8-3/4 rear, or chasing a howl that rises with road speed in a Charger, Road Runner, Challenger or Cuda, starts with knowing which third member you have. The Allstar ALL68531 is the bearing and installation kit for the 489 casting, the case with the big number 9 cast into its side, built with 1.796 inch inside-diameter carrier bearings. It supplies the wear parts a ring and pinion swap needs so you are not setting new gears on old bearings.
The 8-3/4 is a removable third member design: the ring, pinion and carrier live in a cast center section that unbolts from the front of the housing. The pinion rides on two tapered bearings, and its depth is set by a shim behind the inner bearing cone while a crush sleeve sets pinion bearing preload. Unlike many axles, the carrier side is set with threaded adjusters in the bearing caps, which move the ring gear for backlash and load the carrier bearings. Allstar describes ALL68531 as a differential installation kit with bearings, crush sleeve, gaskets, hardware, seals, shims and thread locker for the 8.75 inch 489 case. Our listing also notes a new pinion nut and gear marking compound so you can read the contact pattern.
Pull the center section or look at the left side of the case through the wheel well. Allstar's kit chart sorts 8-3/4 kits by the large cast number: a 9 marks the 489, a 2 marks the 742, and the 741 is usually marked with an X. The 489 has the large tapered 1-7/8 inch pinion stem. Then check the carrier bearings: Allstar makes this kit for 1.796 inch inside-diameter carrier bearings and a separate kit for 489 cases that carry 2.000 inch carrier bearings, so measure the old cone bore or the carrier journal before ordering. Our Chrysler 8.75 problems and rebuild cost guide walks through telling the three cases apart.
This kit fits the Chrysler 8-3/4 rear with the 489 center section and 1.796 inch carrier bearings, which per our listing covers most 1969-1973 Mopar cars and trucks that came with the 8-3/4. It does not fit the 741 or 742 cases. Cars were often fitted with a junkyard center section over the years, so go by the casting on your case rather than the model year, or send us the year, model and casting number and we will check it. More bearing and setup parts are in our rebuild kits category, and loose hard parts are under hard parts.
Press the new inner pinion bearing on over your depth shim, drive in the new races, and tighten the pinion nut in small steps until the crush sleeve gives the preload your gear maker calls for; overshooting means starting again with another sleeve. Many builders skip that fight with a Chrysler 8.75 crush sleeve eliminator kit, which sets preload with a solid spacer and shims. Set backlash with the threaded adjusters, lock them, and confirm the pattern with marking compound, as covered in our backlash and pinion depth setup guide. This kit does not service the axle ends; if the axle bearings are rumbling or the seals leak onto the brakes, the Yukon 8.75 axle bearing, adjuster and seal kit handles both sides. Fill with a quality GL-5 gear oil (add friction modifier if it is a Sure-Grip), and follow the new gear break-in procedure before any hard launches.
| Part number | Allstar ALL68531 |
| Fits | Chrysler 8-3/4 in rear, 489 case, 1-7/8 in tapered pinion bearing, most 1969-1973 |
| Includes | Pinion and carrier bearings, pinion seal, pinion depth shims, carrier shims, crush sleeve, pinion nut, silicone, gear marking compound |
| Shipping weight | 7 lb |
Doing this repair right usually means replacing these at the same time. Same transmission, ships together.
Look for the large number 9 cast on the side of the center section. A large 2 means a 742 case and an X usually means a 741, and those take different kits.
No. Allstar makes this kit for 489 cases with 1.796 inch inside-diameter carrier bearings and a different kit for 489 cases with 2.000 inch carrier bearings. Measure the carrier bearing bore or journal before ordering.
No. It is the bearings, seal, shims, crush sleeve and hardware for the install. The ring and pinion and gear oil are bought separately.
The 8-3/4 sets backlash and carrier bearing preload with threaded adjusters in the bearing caps, so the shimming work is on the pinion depth side.
It is not worth it. Old bearings and a used crush sleeve make it hard to hold correct preload, and a bad setup shows up as gear whine that new gears cannot fix.
No. This kit covers the center section and pinion seal. Axle bearings and seals at the wheel ends need their own kit.
