Yukon Gear Ring & Pinion Gear Set For Chrysler 11.5in in 2014+ RAM 2500 4.88 Ratio
If your 2014 or newer Ram 2500 now rolls on 35 or 37 inch tires and feels like it lost a gear, or the rear axle has started to whine on the highway, this is the gear set built for that truck. Yukon part number YG C11.5B-488B is a 4.88 ratio ring and pinion for the American Axle 11.5 in. rear that Ram put under the coil-spring 2500 starting with the 2014 model year. Yukon catalogs it separately from its 2003-2013 Ram and GM 11.5 gear sets, so order by your truck's year.
The pinion is driven by the rear driveshaft and turns the ring gear bolted to the carrier, which spins the 30-spline full-float axle shafts. The ratio is how many times the driveshaft turns for one turn of the tires. Going to 4.88 from a factory ratio means the engine and transmission work in a lower, stronger part of their range, which brings back the launch and towing feel that taller tires took away. It also keeps the transmission from hunting between gears on grades. The tradeoff is higher cruise RPM, so 4.88 makes the most sense with big tires or a truck that works hard off-road.
Bearing noise and gear noise sound alike. Bearings usually drone at a steady speed regardless of load, while gear whine shifts with throttle. Our whine on acceleration vs deceleration guide walks through the road test, and the AAM 11.5 problems and rebuild cost guide covers the common failures in this axle. Read the axle tag for your current ratio, then use the re-gear after bigger tires guide to check that 4.88 fits your tire size.
This set is designed for the 2014-and-up Ram 2500 with the Chrysler/AAM 11.5 in. rear axle, which uses a 14-bolt cover. Yukon's own compatibility list names the 2014 through 2019 Ram 2500. The 2019 model year began a new heavy-duty generation, and Yukon lists separate 2019-and-up 11.5 gears and kits, so 2019 owners should confirm by VIN. Ram 3500 trucks are not on the listing, and 2003-2013 trucks should shop the earlier 11.5 sets. A 4x4 truck also needs the AAM 9.25 front axle changed to 4.88 so the axles match. Send your year and VIN and we will confirm, or look at the 2014-2018 Ram 11.5 / 9.25 4.56 gear package if you want a milder ratio with front and rear gears in one order.
New gears require a full setup: pinion depth, pinion bearing preload, backlash and carrier bearing preload, then a contact pattern check with marking compound. Yukon's set-up chart for the 2018-and-older 11.5 AAM lists a 0.055 in. OEM pinion shim, 20-30 in-lb of preload on new pinion bearings, 0.006-0.011 in. backlash, and 175 ft-lb on the ring gear bolts. Use new bearings and races rather than the old ones; the Yukon master overhaul kit for the 2014-up Ram 2500 11.5 is matched to this axle. A 4.88 ratio adds load on the carrier, so this is also the time to look at a Dura Grip limited slip for the 30-spline 11.5 and a Hardcore 11.5 cover for added protection.
Fill with the GL-5 gear oil grade Ram specifies for your truck, with friction modifier if you run a clutch-type limited slip. Follow the ring and pinion break-in procedure: Yukon calls for 15 to 20 easy miles then a cool-down, no heavy acceleration for 100 miles, no towing for at least 500 miles, short cool-down cycles on the first tow, and a gear oil change at 500 miles.
| Brand | Yukon Gear & Axle |
| Part number | YG C11.5B-488B |
| Fits | Yukon Gear Ring & Pinion Gear Set For Chrysler 11.5in in 2014+ RAM 2500 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.
If it has the AAM 11.5 in. rear axle with the 14-bolt cover, yes. That axle is what this 2014-and-up set is designed for. Check the axle tag or send your VIN and we will confirm.
Yukon lists the 2014 through 2019 Ram 2500, but 2019 started a new heavy-duty generation with its own 11.5 gears and kits, so confirm a 2019 by VIN. Ram 3500 trucks are not listed for this set.
On a 4x4, yes. The AAM 9.25 front axle must match the rear ratio or the transfer case and tires will fight each other in four-wheel drive. Order a 4.88 front set for the 9.25 at the same time.
All pinion and carrier bearings and races, the pinion seal, crush sleeve or shims, and ring gear bolts. The Yukon master overhaul kit for the 2014-up Ram 2500 11.5 covers those parts.
No. Yukon asks for at least 500 miles of light driving before towing, short cool-down cycles on the first tows, and a gear oil change at 500 miles to keep the warranty.
