The Dana 44 rear is the right axle for a stock-to-mild build. Under 35" and moderate trail pressure, the stock shafts hold up. Push harder and upgrade to Yukon chromoly shafts before you break one on the trail.
All 1966–1977 Broncos use a full-floating Dana 44 rear axle. Full-floating means the axleshafts carry only rotational load — the housing bears the vehicle's weight — so shaft removal doesn't require jacking the vehicle.
Key specs:
Ring gear diameter: 8.5 in
Axleshaft: 27-spline (1966–1972) or 30-spline (1973–1977)
Differential: open from factory; Ford Limited-Slip (Traction-Lok) available on some years
Housing: 3-bolt axleshaft flange
**Spline count matters:** 27-spline shafts are weaker. If you're running more than 33" tires or using a locker aggressively, upgrade to a 30-spline carrier and Yukon chromoly shafts ($320/pair).
**Differential upgrades:**
Eaton Detroit Truetrac (helical gear LSD): $340. Transparent operation, no maintenance, good for daily driving and mild trail. Pairs well with a front locker.
ARB Air Locker: $580 + compressor. True positive lock front and rear; the trail standard for serious use. Requires air line installation and a compressor.
Aussie Locker (automatic locking): $200. Budget option. Clicks and clunks but locks reliably. Fine for dedicated trail trucks.
Why it works
full-floating design (shafts pull without jacking)
30-spline shafts are strong
locker options widely available
good parts availability
Trade-offs
27-spline early trucks are weak — identify before wheeling hard
open from factory
8.5" ring gear limits maximum pinion torque vs. Dana 60
Parts
Part
Vendor
Est. price
Eaton Detroit Truetrac for Dana 44 (27-spline)
Eaton
~$340
ARB Air Locker for Dana 44 rear (30-spline)
ARB
~$580
Yukon chromoly rear axleshafts (30-spline)
Yukon Gear
~$320
Sources
{'title': 'Early Bronco Dana 44 rear axle identification', 'url': 'https://www.broncodriver.com/axles'}
Written and maintained by an AZ wheeler and driveway wrencher. Always cross-reference your factory service manual — modifications affect vehicle safety and warranty. Work at your own risk.