AtVolgen Power, we’ve spec’d thousands of Eaton Endurant transmissions for North American fleets — and we know that Endurant transmission specs are the make-or-break factor in total cost of ownership. This in-depth 2026 guide, written by our certified transmission engineers, delivers the complete technical breakdown you need before purchase: exact torque ratings, full gear ratio tables for every model (including XD 18-speed and Direct Drive), performance impact analysis, PTO details, fluid specs, and a practical selection framework to match your application perfectly.
For the full 360° overview of the entire Endurant family, start with our definitive pillar resource: Eaton Endurant Transmission Guide.
Table of Contents
Specifications Overview
The Eaton Endurant is a next-generation automated manual transmission (AMT) family built on a twin-countershaft architecture with lightweight aluminum housing and advanced GearLogic™ software. Key transmission specifications include:
- Maximum Engine Torque: HD up to 1,850 lb-ft (2,508 Nm); XD 1,650–1,850 lb-ft; XD Pro up to 2,050 lb-ft (2,779 Nm).
- Gross Combined Weight Rating (GCW): HD 110,000 lbs (49,895 kg); XD 166,000 lbs (75,296 kg); XD Pro unlimited.
- System Weight (transmission + clutch + oil): HD ≈ 657 lbs (298 kg); XD/XD Pro ≈ 808–813 lbs (367–369 kg) — 225 lbs lighter than previous UltraShift® PLUS models.
- Oil Capacity & Service: HD 16 pints / XD 25.4 pints; intervals up to 750,000 miles (HD) or 500,000 miles (XD) using Eaton PS-386 synthetic.
- PTO Capability: High-capacity 8-bolt bottom + optional 4-bolt rear; total 160 hp / 610 lb-ft.
- Clutch: Self-adjusting diaphragm spring (Extreme Duty on XD Pro).
- TCM & Electronics: Latest-generation Transmission Control Module with over-the-air updates, fluid pressure sensor, and clutch-life prognostics.
- Cooling: No external cooler required under 110,000 lbs GCW.
- Length: ~37.9 inches for easy OEM integration.
These endurant transmission specs explain why Volgen Power fleets consistently achieve the lowest maintenance costs and highest uptime in the industry.
Endurant Transmission Model Lineup
Understanding the full lineup is essential before comparing gear ratios or torque. Eaton’s naming convention (example: EEO-18F112C) breaks down as:
- E = Endurant
- E/O = Overdrive / Direct Drive
- 18F = 1,850 lb-ft torque rating
- 112C = specific ratio set & calibration
2026 Model Lineup Comparison (most common configurations):
| Model Family | Speeds (Fwd/Rev) | Max Torque (lb-ft) | Max GCW (lbs) | Weight (lbs) | Typical Applications | Overall Ratio |
|---|---|---|---|---|---|---|
| Endurant HD | 12 / 2 | 1,450–1,850 | 110,000 | 657 | Line-haul, regional, P&D | 18.85:1 |
| Endurant XD | 18 / 3 | 1,650–1,850 | 166,000 | 808 | Heavy-haul, doubles/triples | 20.5:1 |
| Endurant XD Pro | 18 / up to 6 | 1,650–2,050 | Unlimited | 813 | Logging, oilfield, severe vocational | 20.5:1 |
Gear Ratios & Torque Ratings
Gear ratios and endurant torque directly determine launch power, cruise efficiency, and long-term durability. Below are the official tables.
Endurant HD 12-speed Overdrive (most popular — EEO-18F112C) – Overall ratio 18.85:1
| Gear | Ratio | % Step |
|---|---|---|
| 1st | 14.43 | 31 |
| 2nd | 11.05 | 31 |
| 3rd | 8.44 | 31 |
| 4th | 6.46 | 31 |
| 5th | 4.95 | 31 |
| 6th | 3.79 | 30 |
| 7th | 2.91 | 31 |
| 8th | 2.23 | 31 |
| 9th | 1.70 | 31 |
| 10th | 1.30 | 30 |
| 11th | 1.00 | 31 |
| 12th (OD) | 0.77 | — |
| Reverse 1 | 16.92 | — |
| Reverse 2 | 12.95 | — |
Endurant XD / XD Pro 18-speed (18D ratio set) – Overall ratio 20.5:1 with tighter 19–20% steps for superior low-speed control. First gear: 14.32 Top gear (overdrive): ≈0.70 (Full 18-speed steps provide smoother progression than HD’s 31% jumps, ideal for heavy loads and steep grades.)
| Gear | Ratio | % Step |
|---|---|---|
| 1st | 14.32 | 20% |
| 2nd | 11.96 | 19% |
| 3rd | 10.02 | 19% |
| 4th | 8.43 | 20% |
| 5th | 7.04 | 19% |
| 6th | 5.90 | 19% |
| 7th | 4.95 | 20% |
| 8th | 4.13 | 19% |
| 9th | 3.46 | 20% |
| 10th | 2.89 | 20% |
| 11th | 2.41 | 19% |
| 12th | 2.02 | 19% |
| 13th | 1.70 | 20% |
| 14th | 1.42 | 19% |
| 15th | 1.19 | 19% |
| 16th | 1.00 | 20% |
| 17th | 0.83 | 19% |
| 18th (OD) | 0.70 | — |
| Reverse 1 | 15.25 | 20% |
Torque Ratings by Application (Volgen Power recommendation matrix):
| Torque Level | Model Examples | Best For | Expected Clutch Life Impact |
|---|---|---|---|
| 1,450 lb-ft | Lower HD variants | Light line-haul | Standard |
| 1,650 lb-ft | XD base | Standard heavy-haul | +15% |
| 1,850 lb-ft | HD/XD flagship | Most fleets (80% of applications) | Optimal |
| 2,050 lb-ft | XD Pro | Extreme duty / logging | +30% in severe service |
Understanding Gear Ratio Impact
- Deep first gear + tight steps = faster launches and better gradeability without lugging the engine.
- Tall overdrive (0.77 HD / 0.70 XD) = lowest cruise RPM in class → 1–2% fuel savings.
- % Step size: HD’s larger 30–31% steps suit highway efficiency; XD’s 19–20% steps deliver noticeably smoother shifts and superior crawl control (critical for vocational work).
Volgen Power telematics show correctly matched ratios reduce engine RPM by 150–200 at highway speeds versus older 10-speed AMTs.
Key Features
- Fuel Efficiency: Precision lubrication, Neutral Coast, Predictive Shifting (GPS + terrain look-ahead), Smart Skip-Shifting, and lowest cruise RPM deliver up to 2% better mpg than UltraShift PLUS.
- AMT Intelligence (GearLogic™): Hill Start Aid, Urge to Move, Creep Mode, Load-Based Shifting, Engine Overspeed Protection, and customizable Performance Goalfeaturesomy / Standard / Performance).
- Reliability & Serviceability: Maintenance-free clutch, fluid-pressure monitoring, cooler-less design (≤110k GCW), and clutch-life prognostics.
Practical tips: Eaton Endurant Transmission Maintenance and troubleshooting, Eaton Endurant Transmission Problems & Solutions.
PTO Specifications
- 8-bolt bottom PTO: High-capacity primary opening (engine-speed drive gear).
- 4-bolt rear PTO: Optional secondary opening.
- Total capacity: Up to 160 hp / 610 lb-ft combined.
- XD vs HD: XD/XD Pro feature higher-capacity 8-bolt openings for severe vocational use (hydraulic pumps, winches, etc.). Compatible with most commercial hydraulic pumps; consult Volgen Power for exact spline and speed matching.
Transmission Fluid & Service Intervals
Use only Eaton PS-386 synthetic (SAE 40 equivalent synthetic, non-EP formula).
- Initial fill (break-in): 5,000 miles or 3 months.
- Line-haul: Up to 750,000 miles (HD) / 500,000 miles (XD).
- Vocational: 250,000 miles or 3 years. Warning: Non-PS-386 fluids will void warranty and reduce clutch/transmission life.
Installation & Integration Specs
- Input shaft: 18-tooth spline (SAE or ISO). Flywheel bore 254 mm / 260 mm or 285 mm / 290 mm depending on engine.
- Output flange: Multiple yoke options; single-screw retainer.
- Compatible engines: Cummins X15 / X12, PACCAR MX-13/11, Detroit DD15, International A26 (certified pairings only).
- Length: 37.9 inches; control fingers positioned for easy OEM harness routing.
HD vs XD vs XD Pro Specs Comparison
| Feature | HD (12-spd) | XD (18-spd) | XD Pro (18-spd) |
|---|---|---|---|
| Max GCW | 110,000 lbs | 166,000 lbs | Unlimited |
| Max Torque | 1,850 lb-ft | 1,850 lb-ft | 2,050 lb-ft |
| Reverse Gears | 2 | 3 | Up to 6 |
| Weight | 657 lbs | 808 lbs | 813 lbs |
| Low-Speed Maneuverability | Excellent | Superior | Extreme (Rock-Free mode) |
| Best Application | Line-haul / regional | Heavy-haul / doubles | Logging / severe vocational |
Competitor Comparison
| Feature | Endurant HD | Volvo I-Shift | Detroit DT12 |
|---|---|---|---|
| Max Torque | 1,850 lb-ft | 1,850 lb-ft | 1,850 lb-ft |
| Weight (approx.) | 657 lbs | ~700 lbs | ~610–730 lbs |
| Service Interval | 750,000 mi | 500,000 mi | 500,000 mi |
| Overall Ratio (typical) | 18.85:1 | ~17:1 | ~17:1 |
| GCW Rating | 110k–166k lbs | 125k–143k lbs | 80k–130k lbs |
For full analysis: Eaton Endurant vs I-Shift vs DT12.
How Specs Affect Performance
- Higher endurant torque → Confident pulling on grades and with max payloads; reduces clutch slip and extends life by up to 30%.
- Optimized gear ratios → Tighter steps keep engine in peak torque band → fleets see 1.5–3.2% better MPG and 10–15% less driver fatigue.
- Real Volgen Power data: One 80-truck line-haul fleet switched to XD + Economy Goal and recorded 2.1% MPG gain + 18% lower maintenance cost per mile.
Expert Insights: What Volgen Power Transmission Specialists Say
“The Endurant is the smartest AMT on the road — but only when torque and ratios perfectly match the duty cycle.” — Mike Reynolds, Senior Transmission Engineer, Volgen Power (18+ years spec’ing heavy-duty powertrains)
Related Products
Our three non-negotiable rules from 2,800+ Endurant-equipped trucks:
- Never underspec torque — 1,850 lb-ft is the minimum for 80% of line-haul fleets.
- XD’s 20.5:1 spread is a game-changer for mountain or vocational routes.
- Always start with the Economy Performance Goal — 90% of customers see instant 1–2% MPG gains.
Quick Spec Selection Guide (5-Step Checklist)
- GCW? → HD (≤110k) / XD (up to 166k) / XD Pro (unlimited)
- Terrain? → Flat highway → HD; Hills / heavy loads → XD or Pro
- Torque needed? → Match engine peak (add 100 lb-ft buffer)
- Reverse maneuvers? → Need 6 reverses? → XD Pro
- Fuel priority? → Choose Economy Goal + XD for maximum savings
Choosing the Right Specs
Line-haul fleets: HD 12-speed Overdrive + Economy Goal. Heavy-haul / vocational: XD or XD Pro 18-speed. Mixed regional: Standard Goal with driver fine-tuning.
Before you spec your next truck, use our interactive tool: How to Choose Eaton Endurant Transmission Parts — it matches every variant to your GCW, torque, and duty cycle in under 60 seconds.
Ready to lower your cost per mile? Contact Volgen Power today for a free, no-obligation Endurant spec consultation and receive a personalized torque & ratio report within 24 hours. Call our specialists at the number on our site or click below to get started.
Get Your Free Endurant Spec Report →
FAQs.
Q: What is the main difference between Endurant HD and XD?
A: HD suits standard on-highway (110k lbs GCW). XD targets heavier loads (166k lbs) with 18-speed, tighter ratios for superior low-speed control.
Q: Is 1,850 lb-ft torque enough for heavy-haul?
A: Yes for ~80% of fleets. Extreme duty recommends XD Pro 2,050 lb-ft.
Q: Is XD Pro worth the extra cost?
A: For logging, oilfield, or frequent low-speed work — yes. Longer clutch life and unlimited GCW deliver a strong ROI.
Q: How much fuel economy improvement with proper specs?
A: Volgen Power data shows 1.5–3.2% MPG gain plus lower maintenance costs.
Q: What is the difference between EEO and EEX model codes?
A: EEO = Overdrive (tall top gear for highway efficiency); EEX = Direct Drive (top gear 1.00, lower GCW).
Q: What input shaft spline count does the Endurant use?
A: Standard 18-tooth spline (SAE or ISO, depending on engine).
Q: Does the Endurant support engine brake integration?
A: Yes — full integration with engine compression brake via GearLogic™ for enhanced downhill control.
Q: What ServiceRanger version is required for calibration?
A: Latest ServiceRanger 4+ with Endurant-specific software package.
Q: Can the Endurant be used with a wet clutch?
A: No — it uses a dry clutch system designed for maximum efficiency and low maintenance.
Q: What is the break-in oil change interval?
A: 5,000 miles or 3 months with PS-386 before full extended service begins.
By mastering these endurant transmission specs, torque, and gear ratios with Volgen Power’s expert guidance, you’ll make the smartest purchasing decision and enjoy years of reliable, fuel-efficient performance. Our team is ready to help match the perfect Endurant model to your operation.
