Yukon Gear High Performance Gear Set For Ford 8.8in in a 3.55 Ratio
A 3.55 is the all-round ratio for the Ford 8.8 rear. It is the gear Mustang owners swap in to replace a lazy 2.73 or 3.08, the ratio F-150 and Expedition owners pick after stepping up one tire size, and a common factory ratio that wears out and starts to whine on high-mile Explorers, Rangers and Crown Victorias. The Yukon Gear & Axle YG F8.8-355 is a new 3.55 ring and pinion for the standard-rotation 8.8 used in Ford cars, trucks and SUVs through 2014.
In the 8.8, the pinion rides on two tapered bearings with a crush sleeve setting preload, and it drives an 8.80 in. ring gear held to the carrier by 10 bolts. With a 3.55 set, the driveshaft makes 3.55 turns for every turn of the axle shafts. Compared with a 3.08 that is about 15 percent more torque at the tires, and compared with a 2.73 about 30 percent more, which is why a 3.55 swap is so noticeable off the line while keeping highway rpm reasonable for a daily driver or a light tow vehicle. Yukon lists this set with a 30-spline pinion.
Read the axle code on the door sticker or the tag under a cover bolt, or mark the driveshaft and a tire, turn the tire one revolution and count driveshaft turns. Our guide to 4R70W gear ratios shows the transmission gearing behind many 8.8 axles, which helps you pick the right final drive for your tire size. If noise is the complaint, use the 4R70W whine and clunk guide to separate transmission noise from rear-axle noise before you pull the cover; a whine that changes between drive and coast and does not follow the shifts is usually in the axle.
This set fits the standard-rotation Ford 8.8 rear. Listed applications include 1983-2014 F-150, 1979-2014 Mustang, 1990-2011 Ranger, 1991-2010 Explorer, 1997-2014 Expedition, 1983-1996 Bronco, 1992-2011 Crown Victoria and Grand Marquis, Thunderbird and E-150 vans, in both solid-axle and IRS versions. It does not fit the 2015-and-later Super 8.8 with the 12-bolt cover or the reverse-rotation 8.8 used as a front axle in IFS trucks. Ford built 8.8 axles with 28 or 31-spline shafts and different inner pinion bearing sizes, and that changes the install kit, not the gears, so send us your year and VIN if you are unsure. Other ratios for the same axle include the Yukon 3.73 set and the Yukon 4.11 set.
Plan on new bearings: the Yukon master overhaul kit for 2009-and-earlier 8.8 axles or the Motive Timken 8.8 master bearing kit covers the pinion and carrier bearings, races, shims and seal. Yukon's setup chart gives the 8.8 a starting pinion shim of 0.026 in., 14-19 in-lb of pinion bearing preload with new bearings, and 60 ft-lb for both the ring gear bolts and the bearing caps. Read the drive and coast pattern with marking compound before the cover goes on. Fill with the grade your manual calls for, usually 75W-140 or 75W-85 gear oil, and add friction modifier on Traction-Lok axles. Break the gears in with easy driving and no towing for the first few hundred miles, then change the oil.
| Brand | Yukon Gear & Axle |
| Part number | YG F8.8-355 |
| Fits | Yukon Gear High Performance Gear Set For Ford 8.8in in a 3.55 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. 2015-and-later F-150 and Mustang rears use the Super 8.8 with a 12-bolt cover and a different pinion. This YG F8.8-355 set is for 2014-and-earlier standard-rotation 8.8 axles.
Torque at the tires goes up about 15 percent over a 3.08 and about 30 percent over a 2.73. Launch and passing get noticeably stronger, and highway rpm rises by the same percentage.
No. Axle spline count is set by the carrier, not the ring and pinion. The gear set is the same; you keep or swap the carrier that matches your axle shafts.
We do not recommend it. Pinion depth and preload change with new gears, and old bearings and a used crush sleeve rarely hold the new settings. Order a master overhaul kit with the gears.
Use the grade in your owner's manual, commonly 75W-140 or 75W-85 gear oil, plus friction modifier on Traction-Lok limited slip axles. Change it after the break-in miles to flush out wear particles.
