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The Dana 80 is about as stout as a factory pickup rear axle gets. It runs an 11.25-inch ring gear, 35-spline full-float axle shafts, a 10-bolt cover and a pinion supported by big tapered bearings set with shims rather than a crush sleeve. It rarely snaps parts. It fails from pinion bearings worn out by towing, leaking hub seals, a tired limited slip, or oil that was never changed.
Which Trucks Have a Dana 80
- Dodge Ram 3500, 1994-2002. The big one. Cummins and V10 duallys and many single rear wheel 3500s got the Dana 80, usually in 3.54 or 4.10 ratio.
- Ford F-350 dually and F-Super Duty, roughly 1989-1998. The one-ton dually and the F-Super Duty chassis got the Dana 80. Super Duty pickups from 1999 on switched to the Sterling 10.5, so a 1999-up pickup is almost never a Dana 80.
- Some GM 1-ton duallys. Most GM 3500s have the 10.5-inch 14-bolt. A few heavy chassis trucks used the Dana 80. Count cover bolts: 14 is a GM 14-bolt, 10 is a Dana 80.
No tag? Look for a cast 80 on the housing. Compare the GM 14-bolt and AAM 11.5.
4.125 vs 4.375 Pinion Bearing: Get This Right First
Dana 80 overhaul kits come in two versions split by the outside diameter of the inner pinion bearing race.
- 4.125-inch OD. Nearly all Dodge Ram Dana 80s, the GM applications and Ford Dana 80s built before 1998. This is the USA Standard Dana 80 master overhaul kit, 4.125 inch OD ($448.90).
- 4.375-inch OD. Some 1998 and later Ford Dana 80s. That axle needs the USA Standard Dana 80 master overhaul kit, 4.375 inch OD ($497.20), or the Yukon Dana 80 master overhaul kit for 98-up Fords ($892.78) with Timken bearings.
How to tell: a Dodge is a 4.125 axle. On a 1998-up Ford, check the build date on the door tag and the axle tag part number. If there is any doubt, pull the pinion before you order and measure the inner race OD with calipers, or read the number etched on the race.
Pinion Bearing Failure
After 150,000-250,000 towing miles the pinion bearings get loose. Symptoms in order: a whine under load that goes quiet on coast, then a clunk on throttle changes, then a growl at all speeds and fine metal on the drain plug magnet. Grab the yoke and push it in and out. Any movement means lost preload.
Do not just tighten the pinion nut. The Dana 80 sets preload with shims behind the outer bearing. The fix is new pinion and carrier bearings, races, seal and the shim pack reset. Check the yoke seal surface too. A grooved yoke eats seals; a Yukon Dana 80 1480 yoke ($265.89) is cheaper than doing the job twice. See the pinion seal leak guide for that side of it.
If only the carrier bearings are rough, the Motive Gear Dana 80 carrier bearing kit ($151.99) covers both sides. Carrier preload and backlash are set with shims outboard of the bearings, so the housing gets spread to pull the carrier. Use a real Dana 30-80 housing spreader ($138.99) with a dial indicator and stay under 0.015 inch of spread.
Hub Bearing and Seal Leaks on the Full-Float
On a full-float axle the weight rides on two tapered hub bearings per spindle, lubricated by gear oil running out the tubes. A hub seal leak puts that oil onto the rear brakes and the inner dually wheel. Oil-streaked inner wheels, grabbing brakes and a low diff with a dry cover gasket point to a hub seal or axle flange gasket.
Pull the shaft and hub, inspect both bearings, replace the seal and any oil-soaked brake friction. Set the locknut to the service spec: seat, back off, final torque, lock tab bent over. Our wheel bearing noise guide covers the noise side.
Trac-Lok Wear, Spools and Lockers
Factory limited slip Dana 80s used a clutch-type Trac-Lok. After 100,000 towing miles the clutches are flat and it spins a wheel on a wet boat ramp. Chatter in turns means worn clutches or no friction modifier. You can rebuild a good case, or swap in the Yukon Trac-Lok positraction internals for Dana 80, 35-spline ($1,011.97).
For a gear-type limited slip that never needs clutches, the Yukon Dura Grip for Dana 80, 4.10 and up ($1,384.96) fits the 4.10-and-numerically-higher carrier break. A 3.54 truck needs the 3.73-and-down version instead.
A spool makes sense on a dedicated tow rig or drag truck. On a daily-driven dually it scrubs tires and pushes on ice. If you still want it, the Yukon steel spool for Dana 80, 4.10 and up ($878.65) is the one. See our open vs limited slip vs locker guide.
Regearing a 3.54 or 4.10 Dana 80
Most Dana 80s left the factory in 3.54 or 4.10. A 3.54 truck pulling heavy lugs and heats the transmission; a 4.10 truck that rarely tows spins high on the highway. The Revolution Gear Dana 80 3.55 ring and pinion ($362.99) replaces worn 3.54 gears, and the Yukon Dana 80 3.73 gear set ($552.68) is a middle ground for a truck that tows sometimes. Going 3.73 to 4.10 crosses the carrier break.
Setup: backlash usually lands around .005-.010 inch, but follow the gear maker's number and the contact pattern. Torque ring gear bolts with thread locker in a star pattern to the gear maker's spec. Our backlash and pinion depth setup guide and regear guide go deeper.
What It Costs: DIY vs Shop
| Repair | DIY | Shop (rough) |
|---|---|---|
| Pinion seal only | About $30-$80 | About $250-$500 |
| Hub seals and bearings, one side | About $80-$200 | About $350-$650 |
| Carrier bearings only | About $150-$200 plus spreader | About $600-$1,000 |
| Full bearing and seal overhaul | About $450-$900 | About $1,300-$2,100 |
| Regear with master kit | Parts about $800-$1,450 | About $2,000-$3,200 |
| Regear plus limited slip or spool | Parts about $1,700-$2,850 | About $3,200-$4,800 |
DIY assumes a dial indicator, inch-pound torque wrench, spreader, press and yoke holder. Capacity is roughly 3 to 4 quarts; fill to the bottom of the fill hole, plus friction modifier for a Trac-Lok. Gear oil is in our fluids section.
Parts and Tools for the Job
| Need | What We Carry |
|---|---|
| Overhaul, 4.125 OD (Dodge, GM, pre-98 Ford) | USA Standard Dana 80 master kit, 4.125 ($448.90) |
| Overhaul, 4.375 OD (98-up Ford) | USA Standard Dana 80 master kit, 4.375 ($497.20) |
| Carrier bearings | Motive Gear Dana 80 carrier bearing kit ($151.99) |
| Spreading the housing | Dana 30-80 housing spreader ($138.99) |
| Worn Trac-Lok | Yukon Trac-Lok internals, 35-spline ($1,011.97) |
| 3.54 gear replacement | Revolution Gear Dana 80 3.55 ring and pinion ($362.99) |
For driveline noise further forward, CoreTransmissionParts.com carries transmission and transfer case rebuild parts.
Fix the Whine Before It Fails
Loose pinion bearings take the gears with them. Replace bearings, races, seal and shims in one pass.
Shop the Dana 80 Overhaul Kit → Gear Oil and FluidsFAQ
How do I know if my Dana 80 takes the 4.125 or 4.375 pinion bearing kit?
Nearly every Dodge, GM and pre-1998 Ford Dana 80 uses the 4.125 inch outside diameter inner pinion bearing race. Some 1998 and later Ford Dana 80s use the larger 4.375 inch race. Check the axle tag and build date, or pull the pinion and measure the old inner race OD with calipers before ordering.
Why is my Dana 80 leaking gear oil onto the rear brakes?
The Dana 80 is a full-float axle, so gear oil runs down the tubes and lubricates the hub bearings. When the hub seal wears, or the axle shaft flange gasket leaks, oil gets onto the brake shoes or pads and the inside of the inner wheel. Replace the seal, inspect the hub bearings and replace oil-soaked brake friction.
How much does a Dana 80 rebuild cost?
A DIY bearing and seal overhaul runs about $450-$900 in parts depending on the kit. A shop overhaul with the existing gears is usually $1,300-$2,100. A regear with new ring and pinion and a full overhaul kit runs about $2,000-$3,200 at a shop, and adding a limited slip or locker pushes it to $3,200-$4,800.
Should I put a spool in a Dana 80 for towing?
Only if the truck is a dedicated tow rig or drag truck. A spool locks both rear wheels together, so a dually scrubs tires in every turn and pushes on wet or icy roads. For a truck that tows and also gets driven daily, a rebuilt Trac-Lok or a gear-type limited slip is the better choice.