Yukon Gear Master Overhaul Kit For Dana 70-U Diff

Complete Rebuild Kit for Dana 70-U Differential (YK D70-U)

The YK D70-U Yukon Gear Master Overhaul Kit is a complete rebuild kit engineered for the Dana Spicer 70-U differential, covering a broad range of Ford, Dodge, and GM heavy-duty trucks and vans from the 1970s through 2012. Built with Timken bearings and races alongside high-quality seals and all required hardware, YK D70-U delivers the precision and durability that the Dana 70-U's heavy-duty applications demand. Yukon's extensive research ensures every component in the YK D70-U is a direct fit, eliminating guesswork and incomplete parts sourcing on this classic but demanding differential.

Features and Benefits

• Timken bearings and races for maximum load capacity and service life in heavy-duty use
• Complete shim kit for precise pinion depth and carrier bearing preload
• All seals included to prevent fluid loss after rebuild
• Ring gear bolts and pinion nut included for complete hardware replacement
• Oil baffles and slingers maintain proper differential lubrication
• Thread locker and marking compound with brush for accurate gear setup
• Gasket included for proper cover resealing
• Covers a wide range of Ford F-350, Dodge, and GMC heavy-duty truck and van applications
• More tailor-made kits than any other manufacturer ensures exact Dana 70-U fitment
• 1-year manufacturer warranty on all included components

Vehicle Fitment

Specifications

What's Included

• Timken carrier bearings and races
• Timken pinion bearings and races
• Pinion seal
• Axle seals
• Complete shim kit
• Ring gear bolts
• Pinion nut
• Oil baffles and slingers
• Thread locking compound
• Marking compound with brush
• Gasket

Frequently Asked Questions

What vehicles use the Dana 70-U differential?
The Dana Spicer 70-U is a heavy-duty rear differential found in a wide range of Ford, Dodge, and GMC trucks and vans from the 1970s through the early 2000s, including Ford F-350, E-350, Dodge Ram 2500/3500, D350, B350, W350, and GMC C3500, K3500, G3500 models. The YK D70-U covers this full range of applications.

Does the YK D70-U include a crush sleeve?
No. The YK D70-U does not include a crush sleeve, as the Dana 70-U uses a solid spacer setup for pinion bearing preload rather than a crush sleeve. Pinion preload is set by selecting the correct solid shim from the included complete shim kit.

Does this kit include bearings and seals?
Yes. The YK D70-U includes Timken carrier bearings and races, Timken pinion bearings and races, a pinion seal, and axle seals. Everything required for a complete bearing and seal replacement is included.

Will the YK D70-U void my vehicle warranty?
Under the Magnuson-Moss Warranty Act, a vehicle manufacturer cannot void your warranty solely because you used aftermarket parts, unless they can demonstrate the part caused the specific failure. Using YK D70-U for a differential rebuild does not automatically invalidate any remaining factory warranty coverage.

Is there a break-in procedure after installing this kit?
Yes. Vary vehicle speed for the first 500 miles after installation and avoid sustained high-speed or heavy towing operation. Inspect for fluid leaks at 100 miles. This allows the Timken bearings and gear tooth surfaces to fully seat and ensures proper preload stability.

What tools are needed to install this kit?
A hydraulic bearing press is required for carrier and pinion bearing installation and removal. You will also need a dial indicator for backlash measurement, an inch-pound torque wrench for pinion preload, a foot-pound torque wrench for ring gear and axle hardware, a seal driver set, and a flange holding tool for pinion nut torque.

How do I set pinion preload on the Dana 70-U?
The Dana 70-U uses solid pinion bearing spacers rather than a crush sleeve. Pinion preload is set by selecting the appropriate solid spacer shim from the complete shim kit included in the YK D70-U. Start with the thickest shim and remove material until the specified rotational preload (typically 20-40 in-lbs for new bearings) is achieved with a measured flange rotating torque.

What gear oil is recommended for the Dana 70-U after this rebuild?
Use a GL-5 rated 80W-140 gear oil for the Dana 70-U as specified in the applicable factory service manual. Change the oil again at approximately 500 miles after the rebuild to flush any initial break-in particles from the differential.

Installation Instructions

1. Raise and safely support the vehicle. Drain differential fluid and inspect for metal debris.
2. Remove rear axle shafts and disconnect the driveshaft at the differential yoke.
3. Mark and remove the differential bearing caps, then remove the carrier assembly from the housing.
4. Press out old carrier bearings using a bearing separator and hydraulic press.
5. Remove the pinion nut and yoke using a flange holding tool, then drive out the pinion shaft.
6. Press old pinion bearing cups from the housing bores and record the shim stack thickness for reference.
7. Clean all housing bores, carrier surfaces, and all mating faces completely.
8. Press new Timken pinion bearing cups from the YK D70-U kit into the housing bores until fully seated.
9. Select the correct solid pinion depth shim from the included shim kit using a pinion depth gauge or pattern method.
10. Install the front Timken pinion bearing and press in the new pinion seal from the kit.
11. Install the pinion yoke and tighten the new pinion nut to achieve the specified rotational preload (20-40 in-lbs for new bearings) measured with an inch-pound torque wrench.
12. Press new Timken carrier bearings onto the carrier, then lower the carrier into the housing.
13. Set carrier bearing preload and backlash using the shim set; target backlash is typically 0.005-0.008 inches for the Dana 70-U.
14. Verify gear tooth contact pattern using the included marking compound and brush, adjusting shims as needed.
15. Install bearing caps in their original orientation, apply thread locker to cap bolts, and torque to specification.
16. Install new axle seals, reinstall axle shafts, reconnect the driveshaft, and fill with appropriate gear oil.
17. Perform the 500-mile break-in procedure and inspect for leaks at 100 miles.

Prop 65 Warning: This product can expose you to chemicals including arsenic, which is known to the State of California to cause cancer. For more information, go to www.P65Warnings.ca.gov.