Commercial Truck Axle
Meritor MT-14X (tandem drive, 40K-46K, highway)
Meritor (now Cummins-Meritor) · Tandem Drive axle · 46,000 lb GAWR
Class 8
In production
Tandem Drive
Manufacturer
Meritor (now Cummins-Meritor)
Type
Tandem Drive
GAWR
46,000 lb
Class
Class 8
What this axle does
The Meritor MT-14X is Meritor's flagship highway tandem drive axle — direct competitor to Dana Spicer D-46-170HP. 40,000-46,000 lb GAWR. Meritor (now Cummins-Meritor after Cummins acquired Meritor in 2022) is one of the two dominant North American truck axle suppliers along with Dana. The MT-14X is widely fitted across all major OEMs — fleet buyers can usually choose between Dana D-46-170HP and Meritor MT-14X as spec options on the same truck.
Specifications
- Manufacturer
- Meritor (now Cummins-Meritor)
- Type
- Tandem Drive
- GAWR
- 46,000 lb
- Ratio options
- 2.47, 2.50, 2.64, 2.85, 3.08, 3.36, 3.55, 3.73, 4.10
- Truck class
- Class 8
- Production
- 2014–present
- Applications
- Long haul, regional, fleet (highway-optimized)
Design and engineering
Tandem drive with optimized hypoid gearing. Lighter weight than competing axles (Meritor advertises 50 lb savings vs equivalent Dana). Inter-axle differential lockout. Optional air-disc brake mounts.
Generations and major changes
- MT-14X Original (2014–2018)Launch.
- MT-14X 14XE (2019–present)Hybrid + BEV-compatible variants added.
Reliability and longevity
Very reliable. Comparable to Dana D-46-170HP. Meritor parts network is global.
Common problems
Pinion seal leaks at 400K-600K miles (similar to Dana). Inter-axle differential lockout solenoid wear.
Maintenance schedule
Differential lube every 250K miles (synthetic). Inter-axle every 150K.
Pros and cons
Pros
- ✓Lightweight design (50 lb savings vs Dana)
- ✓Cummins-Meritor integrated supplier (post-2022)
- ✓Industry-standard reliability
- ✓Wide OEM availability
Cons
- !Pinion seals are recurring maintenance
- !Cummins acquisition is consolidating supplier choice
Resale value impact
Standard.
Trucks that use this axle
Related
Frequently Asked Questions
What is the Meritor MT-14X (tandem drive, 40K-46K, highway) GAWR?
The Meritor MT-14X (tandem drive, 40K-46K, highway) is rated for 46,000 lb Gross Axle Weight Rating (GAWR). GAWR is the maximum weight the axle can support, including the chassis, suspension, body, and payload distributed to that axle. For a tandem-drive configuration, the rating is the combined capacity of both rear axles. Steer axles typically range 12,000-22,000 lb depending on application; tandem drives range 38,000-58,000 lb.
What gear ratios are available for the Meritor MT-14X (tandem drive, 40K-46K, highway)?
The Meritor MT-14X (tandem drive, 40K-46K, highway) offers these ratio options: 2.47, 2.50, 2.64, 2.85, 3.08, 3.36, 3.55, 3.73, 4.10. Lower numerical ratios (e.g., 2.47, 2.64) are taller — better for highway fuel economy at the cost of acceleration. Higher numerical ratios (e.g., 4.10, 4.56) are shorter — better for vocational/severe-duty starts and grade-climbing at the cost of highway fuel economy. Fleet spec engineers select the ratio based on average loaded weight, terrain, and target cruise speed.
What's the difference between a single drive and tandem drive axle?
A single-drive axle has one driven rear axle — typical of Class 6-7 medium-duty trucks. A tandem-drive axle has two driven rear axles connected via an inter-axle differential — typical of Class 8 trucks. Tandems provide more traction, allow heavier loads (40,000-58,000 lb combined GAWR vs 23,000-32,000 lb single-drive), and better handle severe-duty/loose-surface conditions because both rear axles can drive. The trade-off: more weight, more cost, more components to service.
How long should the Meritor MT-14X (tandem drive, 40K-46K, highway) last?
For highway-duty Class 8 axles, expect 1,000,000+ miles before major hypoid gear or pinion overhaul, with proper synthetic-lube service intervals (every 250,000 miles). Vocational/severe-duty axles see 600,000-800,000 miles before similar service due to higher load cycling and frequent inter-axle differential lockout engagement. Steer axles last similarly long for the bearings and gears, but king-pins typically need replacement at 750,000-1,000,000 miles in highway use (500K-700K in severe-duty).
How do I know if my axle needs service?
Warning signs: differential lube leak at the pinion seal (visible under the rear of the truck), hypoid gear noise (whine that varies with throttle), wheel bearing growl (changes pitch with speed), king-pin slop (steering wander or clunking on turns). For preventive: pull a lube sample at every PM service and have it analyzed — metal content trending up signals internal wear before it becomes a failure. Most fleets pull samples at 100K and analyze every 250K.
Can I swap a Dana axle for a Meritor (or vice versa)?
Generally yes for the same GAWR class — both manufacturers build to similar SAE specifications for major dimensions, suspension mounting points, and brake mounting. However: ratio options differ, wheel bearings differ slightly, axle shafts are NOT interchangeable, and brake controllers may need to be reconfigured for different ABS sensor patterns. For a fleet swap, plan the cross-reference carefully — many fleets choose to standardize on one supplier (all-Dana or all-Meritor) to simplify parts stocking and tech training.