USA Standard Ring & Pinion Replacement Gear Set For Dana 30 Reverse Rotation in a 4.88 Ratio
The USA Standard Gear ZG D30R-488R is a 4.88 ring and pinion for the reverse rotation (high pinion) Dana 30 front axle. The manufacturer's fitment list puts it under the 1984-2001 Jeep Cherokee XJ, the 1986-1992 Comanche MJ and the 1987-1995 Wrangler YJ in 4WD. Most people buying it have put 33 in. or larger tires on an older Jeep and are matching the front axle to a 4.88 rear, or they are chasing a howl from the front diff and want new gears while it is apart. A 4x4 must run the same ratio front and rear, so this set is normally ordered with a matching 4.88 set for the rear axle.
In a high pinion Dana 30 the pinion enters the housing above the axle centerline, so the front driveshaft sits higher and the ring gear turns the opposite way from a rear axle. The teeth are cut for that direction, which is why reverse gears and standard rotation gears are never interchangeable even though both carry a 7.20 in. ring gear. This set uses a 26 spline pinion and 10 ring gear bolts, and USA Standard notes it fits the reverse Dana 30 without a crush sleeve, so pinion bearing preload is set with shims rather than by crushing a sleeve. At 4.88 the pinion is small and the ring gear does most of the work, which is how a deeper ratio multiplies torque to the front tires. Ratio and carrier must agree: our carrier break explainer covers why a carrier that suits a 3.07 or 3.55 front may not accept 4.88 gears.
Look at the front housing from the side. If the driveshaft enters above the axle tubes, you have a high pinion axle; if it enters below, you have a low pinion standard rotation axle and need a different set. Jeep used both styles in this era, so check your axle rather than going by model alone. Read the ratio from the axle tag or count driveshaft turns against tire turns. If noise is the complaint, our guide on whine on acceleration versus coast helps separate gear noise from bearing noise, and the regear after bigger tires guide shows where 4.88 lands for your tire size.
USA Standard lists this 4.88 reverse rotation set for 1984-2001 Cherokee XJ 4WD, 1986-1992 Comanche 4WD and 1987-1995 Wrangler YJ, all on the Dana 30 front. Confirm the high pinion housing, the 26 spline pinion and your current carrier before ordering. If you are unsure, send us your year and VIN, or browse the rest of our axle and hard parts. If you want a slightly taller ratio for 31 to 33 in. tires, we also carry the reverse Dana 30 set in 4.56.
Gears this deep are a setup job, not a bolt-in. Pinion depth is set with shims under the inner pinion bearing, preload with shims on the pinion, and backlash plus carrier bearing preload with shims behind the carrier bearings. The Dana 30 case is tight, so a housing spreader makes carrier removal and installation far safer for the case. Replace every bearing, the pinion seal and the inner axle seals while it is apart; the Yukon Dana 30 front master overhaul kit covers the bearings, shims and seals, and the inner axle seal installer keeps the new seals square in the tubes. Our backlash and pinion depth guide walks through reading the contact pattern. Fill with GL-5 gear oil, then follow a real break-in: short drives that let the axle cool, no towing or hard use for the first 500 miles, then change the oil.
| Brand | Yukon Gear & Axle |
| Part number | ZG D30R-488R |
| Fits | USA Standard Ring & Pinion Replacement Gear Set For Dana 30 Reverse Rotation in a 4.88 Ratio |
| Type | Final Drive Gears |
| Condition | New |
| Ships | Same business day (in stock), from the USA |
| Warranty | 1-year |
Doing this repair right usually means replacing these at the same time. Same transmission, ships together.
No. The TJ front Dana 30 is a low pinion, standard rotation axle and needs a standard rotation short pinion set. This ZG D30R-488R is only for the high pinion reverse rotation Dana 30 found under the XJ, MJ and YJ applications on the manufacturer's list. Check where the driveshaft enters your housing before ordering.
Possibly. Dana 30 carriers are split by ratio range, and a carrier built for a numerically low factory ratio may not let deep gears clear. Check what ratio your Jeep came with and confirm the carrier series before the install day.
New pinion and carrier bearings, the pinion seal, inner axle seals, ring gear bolts and fresh gear oil. A master overhaul kit for the Dana 30 front bundles the bearings, shims and seals so the job only gets done once.
Yes. A 4WD Jeep must run the same ratio front and rear, or the axles fight each other in 4WD. If you put this 4.88 set in the front, the rear needs 4.88 gears too.
Use a quality GL-5 gear oil. Break the gears in with several short drives at moderate speed, letting the axle cool between them, avoid towing or off-road use for the first 500 miles, then drain and refill to remove break-in wear metal.
