MOPAR 8 3/4-INCH SETUP SPECS COMPONENT SPEC Ring gear bolts 55 ft-lb Main cap bolts 90 ft-lb Pinion preload (89) new bearing 14-19 in-lb Pinion preload (89) used bearing 6-9 in-lb Total preload (89) new bearing 30-35 in-lb* Ring gear backlash 0.006 to 0.010 inch *Total preload is a combination of turning the pinion and the ring gear without the axles installed. PARTS LIST DESCRIPTION PN SOURCE PRICE Ford gear additive XL-3 eBay $5.98 Speedi-Sleeve 99187 NAPA 41.49 Yukon 3.55 gearset 24010 Randy's Ring 294.86 Yukon Master Overhaul set 14008 Randy's Ring 131.04 Yukon axle set, 5 x 4.50 21041 Randy's Ring 321.62 Yukon spanner wrench 56027 Randy's Ring 54.77 Yukon bearing race driver HM803110 Randy' Ring 146.10 We've heard the centersection called all kinds of colorful names, such as pumpkin, hog's head, dropout, and pig. Lee worked slowly and carefully, tightening the pinion nut and checking the pinion preload with a dial-type inch-pound torque wrench to work up to the specified 14 to 19 in-lb of preload for new bearings on an 89 case. The used bearing spec for the 89 case is 6 to 9 in-lb.Lee worked slowly and carefully, tightening the pinion nut and checking the pinion preload Lee used a Randy's Ring & Pinion carrier bearing tool to remove the old bearings from the differential. The tool clamps around the bearing and removes it much like a power steering pulley removal tool.Lee used a Randy's Ring & Pinion carrier bearing tool to remove the old bearings from the Lee attached the ring gear to the carrier. All 8 3/4-inch Mopar differentials use lefthand thread, 3/8-inch NF bolts to attach the ring gear to the differential, and the Yukon master install kit includes new bolts. Make sure the gear is fully seated to the ring gear flange and torque all bolts using red thread locker. Never use lock washers under ring gear bolts.Lee attached the ring gear to the carrier. All 8 3/4-inch Mopar differentials use lefthand Lee installed the carrier bearings on the differential. Make sure both bearings are fully seated on the carrier flanges. He used bearing drivers and even an old inner bearing race to ensure the bearings were fully seated.Lee installed the carrier bearings on the differential. Make sure both bearings are fully After Lee set the ring gear and differential in the case, he put white lithium grease on the spanner nuts and made sure the nuts were fully engaged with the threads before installing the main caps. He lightly tightened the main cap bolts to allow the spanner nuts to turn.After Lee set the ring gear and differential in the case, he put white lithium grease on t To set backlash, Lee tightened the left (driver-side) spanner nut to push the ring gear toward the pinion. This will probably require moving the right-side spanner to properly position the ring gear. The right-side spanner determines the preload on the carrier bearings.To set backlash, Lee tightened the left (driver-side) spanner nut to push the ring gear to The backlash spec for most rear gears is a relatively wide range. In this case, it's anywhere from 0.006 to 0.010 inch. Reeves wanted to work toward the minimum spec for better durability and started by adjusting the left-side adjuster to 0.008 inch of backlash.The backlash spec for most rear gears is a relatively wide range. In this case, it's anywh To check the gear pattern properly, Lee painted six gear teeth with the yellow checking paint supplied in the Yukon master install kit. Reeves emphasized that wrapping a rag around the pinion to put a slight load on the bearings is important to getting a proper reading on the pattern.To check the gear pattern properly, Lee painted six gear teeth with the yellow checking pa Here is Lee's final pattern. The first attempt at 0.008 inch indicated the ring gear was too close to the pinion, so Lee increased the backlash 0.002 inch to 0.010 inch to create the pattern shown here.Here is Lee's final pattern. The first attempt at 0.008 inch indicated the ring gear was t This is the coast side of the gear with the tighter 0.008-inch backlash that places the pattern too deep into the ring gear. Increasing the backlash returned the pattern more to the middle of the ring gear teeth.This is the coast side of the gear with the tighter 0.008-inch backlash that places the pa Here is the assembled centersection with the adjuster locks bolted in place. Lee actually bent one slightly to position the lock so he didn't have to risk moving the adjusters since this rear was so backlash sensitive.Here is the assembled centersection with the adjuster locks bolted in place. Lee actually Lee cleaned the carrier gasket surface, installed a new gasket on the studs, slipped the centersection into place, and then torqued the fasteners.Lee cleaned the carrier gasket surface, installed a new gasket on the studs, slipped the c The last step was to slide the new Yukon axles in place. Hudson brought different wheels with the wide bolt pattern only to realize he needed matching brake drums to complete the changeover to the larger Mopar 5x41/2-inch bolt pattern.The last step was to slide the new Yukon axles in place. Hudson brought different wheels w Reeves recommends this Ford XL-3 gear additive and friction modifier in all his installations along with a high-quality 85W-140 gear oil.Reeves recommends this Ford XL-3 gear additive and friction modifier in all his installati New Gear Break-In Once those new gears are installed in the rearend, you must curb your enthusiasm for at least a few hundred miles before you begin flogging those burnouts and dragstrip passes. Randy's Ring & Pinion suggests taking it easy on the new gears, especially for the first 15 to 20 miles, with no hard acceleration, then let the gears cool completely. After that, avoid abuse for the first 100 miles and then change the gear lube after the first 500 miles to get rid of the metal that will inevitably be found in the oil from the new gears and bearings. SOURCES Randy's Ring & Pinion (Yukon Gear) 10411 Airport Road SE Everett WA 98204 866-631-0196 www.ringpinion.com Reeves Rearend Repair 26821 Ruether Ave. Unit G Canyon Country CA 91351 661-252-1400 www.reevesservice.com « | 1 | 2 | View Full Article By Jeff Smith Enjoyed this Post? Subscribe to our RSS Feed, or use your favorite social media to recommend us to friends and colleagues!
