Both are 13-speed Eaton Fuller overdrive transmissions. The RTLO16713A handles up to 1,650 lb-ft of torque, while the RTLO16913A steps up to 1,850 lb-ft. Same gear ratios, different strength rating. Choose the 16713A for standard long-haul work; go with the 16913A if you regularly push heavy loads or run a tuned engine.
If you have spent more than five minutes on a trucking forum, you know the debate. One driver swears by the 16713A, another won't touch anything below the 16913A. Meanwhile you're standing in front of a parts catalogue wondering if the difference is just two numbers and a prayer.
Good news: this isn't complicated once you understand what those numbers actually mean. Let's break it down properly — no filler, no guesswork, just the facts you need to make the right call.
What Does RTLO Actually Mean?
Before comparing two specific models, let's decode the badge. Eaton Fuller uses a naming system that packs a lot of information into a few letters and digits.
R = Roadranger series. T = Twin countershaft design (which spreads torque across two shafts for added strength). L = Low inertia — meaning the transmission responds faster to gear changes, which is a real-world advantage in stop-and-go or mountainous driving. O = Overdrive, so top gear sits below 1:1, giving you better fuel economy at highway speeds.
Then come the numbers. The first three digits — 167 or 169 — represent the nominal torque capacity in hundreds of pound-feet. So RTLO16713A is rated for ~1,670 lb-ft (rounded to 1,650 lb-ft in official specs), and RTLO16913A handles ~1,850 lb-ft. The next two digits, 13, tell you there are 13 forward speeds. The trailing A refers to the ratio set.
RTLO16713A vs RTLO16913A: Side-by-Side Specs
Here's where most buyers want to start. The table below captures the critical technical differences between these two transmissions based on Eaton's official specification data.
| Specification | RTLO16713A | RTLO16913A |
|---|---|---|
| Transmission Type | 13-speed manual overdrive | 13-speed manual overdrive |
| Max Torque Rating | 1,650 lb-ft (2,237 Nm) | 1,850 lb-ft (2,509 Nm) |
| Design | Twin countershaft, low inertia | Twin countershaft, low inertia |
| Overdrive Ratio | 0.73 (top gear) | 0.73 (top gear) |
| Gear Ratio Spread | Identical to 16913A | Identical to 16713A |
| Primary Application | Standard long-haul, vocational | High-torque long-haul, heavy freight |
| Component Weight | Standard | Heavier-duty internals |
| Fuel Economy Impact | Essentially equal | Essentially equal |
| Expected Lifespan (maintained) | 500,000+ miles | 500,000+ miles (longer under heavy use) |
| Resale Value | Strong | Slightly higher |
The gear ratios on both transmissions are the same. Fuel economy is virtually identical. What changes is internal component strength — the 16913A uses beefier gears, shafts, and bearings to handle that additional 200 lb-ft of torque.
The RTLO16713A: A Workhorse That Earns Its Keep
The 16713A is one of the most popular manual transmissions in North American trucking — and that popularity isn't an accident.
It handles up to 1,650 lb-ft of torque, which comfortably covers the vast majority of Class 8 engines running standard factory tunes. As confirmed by Pro Gear and Transmission, it is particularly well suited for "vocational fleets currently operating Eaton manual transmissions" — meaning fleets doing regular delivery, flatbed, and highway hauling work.
The low inertia design (that "L" in RTLO) makes it more responsive than older RT-series boxes. Drivers generally find gear changes feel cleaner and require less synchro fighting, especially when double-clutching at highway speeds.
✅ RTLO16713A Best For
- Standard long-haul operations
- Engines producing up to ~1,650 lb-ft torque
- Fleet operators managing costs
- Drivers who prefer a lighter, more responsive feel
- Vocational and mixed-use trucks
⚠️ RTLO16713A Watch Out If
- You're running a high-tune engine near or above 1,650 lb-ft
- You consistently pull max GCW (Gross Combined Weight)
- You haul in mountain regions with frequent low-range demand
- Your engine is tuned beyond factory specs
The RTLO16913A: When You Need More Muscle
The 16913A is essentially the same transmission architecture, but built tougher. It handles up to 1,850 lb-ft of torque, which makes it the right choice for higher-powered engine configurations.
Experienced TruckersReport forum members confirm this: "13 speed Eaton is rated for 1,650 [and] 18 speed is rated for 1,850 torque." The 16913A breaks that pattern — it puts 1,850 lb-ft capacity into the 13-speed format. That's meaningful if your application demands it.
The heavier-duty internal components — shafts, gears, bearings — give this model more margin in demanding applications. If you're running a C15 Cat, a high-output Cummins, or any engine tuned toward the upper end of the torque range, the extra headroom is not just nice to have, it's the difference between a transmission that lasts and one that doesn't.
✅ RTLO16913A Best For
- High-torque engines (1,650–1,850 lb-ft range)
- Tuned or performance-spec engines
- Consistent heavy hauling near max GCW
- Mountain and severe-duty routes
- Operators prioritising longevity over upfront cost
⚠️ RTLO16913A Watch Out If
- Budget is tight (costs slightly more)
- You're running a standard-output engine — overkill spending
- Weight limits are critical — marginally heavier
Why the Torque Rating Is the Only Number That Matters
Here's a thing that confuses a lot of buyers: transmissions are rated for torque, not horsepower. You can have 600 horsepower under the hood, but it's the torque figure that loads the gears.
This is why experienced drivers on forums like TruckersReport keep stressing the same point: "Most reputable dealers won't crank up the ECM higher than the 1,650 [lb-ft]" when a 16913A is in the truck. The transmission's torque ceiling defines your safe tuning range.
Going beyond that ceiling — especially in low range during heavy pulls — dramatically shortens transmission life. It's not a question of if, it's a question of when. This is the single most important factor when choosing between these two models.
Gear Ratios and Day-to-Day Driveability
This is where drivers expecting a big difference get a pleasant surprise. Both transmissions share the same gear ratio spread, which means the driving experience is nearly identical.
The top gear in both models sits at an overdrive ratio of 0.73:1 — so at highway RPM, you're getting the same fuel efficiency from either box. There's no hidden penalty or bonus in this department for choosing one over the other.
Both use the standard H-pattern with a high/low range selector and a splitter button. If you've driven one, you've essentially driven the other. The only subtle difference some drivers report is a very slightly different feel in the 16913A due to its heavier internals — but it's not something most people would notice during a normal shift.
Lifespan and Maintenance: What to Expect
With proper maintenance, both transmissions routinely exceed 500,000 miles. That's not marketing copy — that's a figure backed by decades of fleet data and driver accounts across trucking communities.
Eaton Fuller recommends 50W synthetic oil as the preferred lubricant for all RTLO-series transmissions. The fill plug is on the left side of the transmission, and the level should be checked at every major service interval. This is basic but critical: more transmissions fail from neglected fluid changes than from overloading.
The 16913A may edge out the 16713A in longevity specifically when used in heavy-duty conditions, simply because its internal components have more strength margin. Under identical, moderate loads, both will last about the same. But push either transmission near its rated limit regularly, and the 16913A's heavier guts become an advantage.
Can You Swap One for the Other?
Yes — and this is one of the more practical advantages of the RTLO series. Both transmissions are dimensionally compatible, so swapping one for the other is achievable without major driveline surgery.
The important caveat: if you're upgrading from a 16713A to a 16913A to support a higher-output engine, make sure the rest of your driveline — particularly the rear axles and driveshafts — can handle the additional torque. The transmission upgrade alone won't protect components downstream that weren't built for the higher load.
For parts availability, both models are widely stocked. Companies like Pro Gear and Transmission carry new and rebuilt units, with same-day shipping on stock items. Rebuilt units come with warranty, and Eaton's own remanufactured programme is also an option for fleet operators who want OEM-level confidence without new-unit pricing.
So Which One Should You Choose?
Here's the short version:
- Standard long-haul with a factory-tuned engine? → The RTLO16713A is your transmission. It's proven, cost-effective, and more than capable for the job.
- High-output engine, regular heavy hauling, or mountain routes? → The RTLO16913A earns its slightly higher price tag by giving you the torque headroom and component strength to last.
- Running a tuned or remapped engine? → Always go 16913A. Pushing a 16713A beyond 1,650 lb-ft regularly is asking for an expensive lesson.
When in doubt, check your engine's rated torque output with your OEM or the tuner, and match the transmission ceiling accordingly.
Frequently Asked Questions
Are the gear ratios identical on both transmissions?
Yes. Both the RTLO16713A and RTLO16913A share the same gear ratio spread, including an identical 0.73:1 top overdrive gear. Fuel economy is effectively the same between models.
How long do these transmissions last?
With correct fluid maintenance and operation within their rated torque limits, both models routinely exceed 500,000 miles. The 16913A may last longer in applications where it is regularly loaded near its rated ceiling, thanks to heavier internal components.
Does the 16913A cost significantly more?
The price difference exists but is not dramatic. The 16913A commands a slightly higher purchase price and generally holds better resale value due to its higher torque rating. Over the life of the truck, the difference is often negligible compared to the cost of rebuilding a mismatched transmission.
Can I convert a 13-speed RTLO to an 18-speed?
No. As confirmed by the Eaton Fuller community, a 13-speed cannot be converted to an 18-speed by simply changing the shift knob. They are fundamentally different transmissions. You can convert an 18-speed to a 13-speed configuration by changing the shift handle — but not the other direction.
What oil should I use?
Eaton Fuller recommends 50W synthetic for optimal performance. If you're using mineral oil, 80W is the alternative recommendation. Synthetic is the better long-term choice for high-mileage applications.
Final Verdict
The RTLO16713A and RTLO16913A are both excellent transmissions from a company with a decades-long track record in heavy hauling. Choosing between them isn't about which one is "better" in some abstract sense — it's about matching the tool to the job.
The 16713A covers the majority of standard trucking applications brilliantly. The 16913A exists for the specific situations where 200 extra pound-feet of torque capacity makes a meaningful difference to component longevity and operational safety.
Know your engine's output. Know your load profile. Match accordingly. It really is that simple — and now you have the information to do it properly.
Sources & References
- Eaton Corporation — Fuller 13-Speed RTLO Series Specification Sheet
- TruckersReport.com — HP Ratings for RTLO16913A (Community Discussion)
- TruckersReport.com — Transmission Ratio Differences — A, B, C Types
- Pro Gear and Transmission — RTLO16713A Eaton Fuller Transmission Listing
- General Truck Parts — Fuller RTLO18913A Specs Overview
- Fleet Owner Magazine — High-Torque Transmissions from Eaton
- Eaton Fuller Transmission Guide 2015 — Full Specification Guide (PDF)
Both are 13-speed Eaton Fuller overdrive transmissions. The RTLO16713A handles up to 1,650 lb-ft of torque, while the RTLO16913A steps up to 1,850 lb-ft. Same gear ratios, different strength rating. Choose the 16713A for standard long-haul work; go with the 16913A if you regularly push heavy loads or run a tuned engine.
If you have spent more than five minutes on a trucking forum, you know the debate. One driver swears by the 16713A, another won't touch anything below the 16913A. Meanwhile you're standing in front of a parts catalogue wondering if the difference is just two numbers and a prayer.
Good news: this isn't complicated once you understand what those numbers actually mean. Let's break it down properly — no filler, no guesswork, just the facts you need to make the right call.
What Does RTLO Actually Mean?
Before comparing two specific models, let's decode the badge. Eaton Fuller uses a naming system that packs a lot of information into a few letters and digits.
R = Roadranger series. T = Twin countershaft design (which spreads torque across two shafts for added strength). L = Low inertia — meaning the transmission responds faster to gear changes, which is a real-world advantage in stop-and-go or mountainous driving. O = Overdrive, so top gear sits below 1:1, giving you better fuel economy at highway speeds.
Then come the numbers. The first three digits — 167 or 169 — represent the nominal torque capacity in hundreds of pound-feet. So RTLO16713A is rated for ~1,670 lb-ft (rounded to 1,650 lb-ft in official specs), and RTLO16913A handles ~1,850 lb-ft. The next two digits, 13, tell you there are 13 forward speeds. The trailing A refers to the ratio set.
RTLO16713A vs RTLO16913A: Side-by-Side Specs
Here's where most buyers want to start. The table below captures the critical technical differences between these two transmissions based on Eaton's official specification data.
| Specification | RTLO16713A | RTLO16913A |
|---|---|---|
| Transmission Type | 13-speed manual overdrive | 13-speed manual overdrive |
| Max Torque Rating | 1,650 lb-ft (2,237 Nm) | 1,850 lb-ft (2,509 Nm) |
| Design | Twin countershaft, low inertia | Twin countershaft, low inertia |
| Overdrive Ratio | 0.73 (top gear) | 0.73 (top gear) |
| Gear Ratio Spread | Identical to 16913A | Identical to 16713A |
| Primary Application | Standard long-haul, vocational | High-torque long-haul, heavy freight |
| Component Weight | Standard | Heavier-duty internals |
| Fuel Economy Impact | Essentially equal | Essentially equal |
| Expected Lifespan (maintained) | 500,000+ miles | 500,000+ miles (longer under heavy use) |
| Resale Value | Strong | Slightly higher |
The gear ratios on both transmissions are the same. Fuel economy is virtually identical. What changes is internal component strength — the 16913A uses beefier gears, shafts, and bearings to handle that additional 200 lb-ft of torque.
The RTLO16713A: A Workhorse That Earns Its Keep
The 16713A is one of the most popular manual transmissions in North American trucking — and that popularity isn't an accident.
It handles up to 1,650 lb-ft of torque, which comfortably covers the vast majority of Class 8 engines running standard factory tunes. As confirmed by Pro Gear and Transmission, it is particularly well suited for "vocational fleets currently operating Eaton manual transmissions" — meaning fleets doing regular delivery, flatbed, and highway hauling work.
The low inertia design (that "L" in RTLO) makes it more responsive than older RT-series boxes. Drivers generally find gear changes feel cleaner and require less synchro fighting, especially when double-clutching at highway speeds.
✅ RTLO16713A Best For
- Standard long-haul operations
- Engines producing up to ~1,650 lb-ft torque
- Fleet operators managing costs
- Drivers who prefer a lighter, more responsive feel
- Vocational and mixed-use trucks
⚠️ RTLO16713A Watch Out If
- You're running a high-tune engine near or above 1,650 lb-ft
- You consistently pull max GCW (Gross Combined Weight)
- You haul in mountain regions with frequent low-range demand
- Your engine is tuned beyond factory specs
The RTLO16913A: When You Need More Muscle
The 16913A is essentially the same transmission architecture, but built tougher. It handles up to 1,850 lb-ft of torque, which makes it the right choice for higher-powered engine configurations.
Experienced TruckersReport forum members confirm this: "13 speed Eaton is rated for 1,650 [and] 18 speed is rated for 1,850 torque." The 16913A breaks that pattern — it puts 1,850 lb-ft capacity into the 13-speed format. That's meaningful if your application demands it.
The heavier-duty internal components — shafts, gears, bearings — give this model more margin in demanding applications. If you're running a C15 Cat, a high-output Cummins, or any engine tuned toward the upper end of the torque range, the extra headroom is not just nice to have, it's the difference between a transmission that lasts and one that doesn't.
✅ RTLO16913A Best For
- High-torque engines (1,650–1,850 lb-ft range)
- Tuned or performance-spec engines
- Consistent heavy hauling near max GCW
- Mountain and severe-duty routes
- Operators prioritising longevity over upfront cost
⚠️ RTLO16913A Watch Out If
- Budget is tight (costs slightly more)
- You're running a standard-output engine — overkill spending
- Weight limits are critical — marginally heavier
Why the Torque Rating Is the Only Number That Matters
Here's a thing that confuses a lot of buyers: transmissions are rated for torque, not horsepower. You can have 600 horsepower under the hood, but it's the torque figure that loads the gears.
This is why experienced drivers on forums like TruckersReport keep stressing the same point: "Most reputable dealers won't crank up the ECM higher than the 1,650 [lb-ft]" when a 16913A is in the truck. The transmission's torque ceiling defines your safe tuning range.
Going beyond that ceiling — especially in low range during heavy pulls — dramatically shortens transmission life. It's not a question of if, it's a question of when. This is the single most important factor when choosing between these two models.
Gear Ratios and Day-to-Day Driveability
This is where drivers expecting a big difference get a pleasant surprise. Both transmissions share the same gear ratio spread, which means the driving experience is nearly identical.
The top gear in both models sits at an overdrive ratio of 0.73:1 — so at highway RPM, you're getting the same fuel efficiency from either box. There's no hidden penalty or bonus in this department for choosing one over the other.
Both use the standard H-pattern with a high/low range selector and a splitter button. If you've driven one, you've essentially driven the other. The only subtle difference some drivers report is a very slightly different feel in the 16913A due to its heavier internals — but it's not something most people would notice during a normal shift.
Lifespan and Maintenance: What to Expect
With proper maintenance, both transmissions routinely exceed 500,000 miles. That's not marketing copy — that's a figure backed by decades of fleet data and driver accounts across trucking communities.
Eaton Fuller recommends 50W synthetic oil as the preferred lubricant for all RTLO-series transmissions. The fill plug is on the left side of the transmission, and the level should be checked at every major service interval. This is basic but critical: more transmissions fail from neglected fluid changes than from overloading.
The 16913A may edge out the 16713A in longevity specifically when used in heavy-duty conditions, simply because its internal components have more strength margin. Under identical, moderate loads, both will last about the same. But push either transmission near its rated limit regularly, and the 16913A's heavier guts become an advantage.
Can You Swap One for the Other?
Yes — and this is one of the more practical advantages of the RTLO series. Both transmissions are dimensionally compatible, so swapping one for the other is achievable without major driveline surgery.
The important caveat: if you're upgrading from a 16713A to a 16913A to support a higher-output engine, make sure the rest of your driveline — particularly the rear axles and driveshafts — can handle the additional torque. The transmission upgrade alone won't protect components downstream that weren't built for the higher load.
For parts availability, both models are widely stocked. Companies like Pro Gear and Transmission carry new and rebuilt units, with same-day shipping on stock items. Rebuilt units come with warranty, and Eaton's own remanufactured programme is also an option for fleet operators who want OEM-level confidence without new-unit pricing.
So Which One Should You Choose?
Here's the short version:
- Standard long-haul with a factory-tuned engine? → The RTLO16713A is your transmission. It's proven, cost-effective, and more than capable for the job.
- High-output engine, regular heavy hauling, or mountain routes? → The RTLO16913A earns its slightly higher price tag by giving you the torque headroom and component strength to last.
- Running a tuned or remapped engine? → Always go 16913A. Pushing a 16713A beyond 1,650 lb-ft regularly is asking for an expensive lesson.
When in doubt, check your engine's rated torque output with your OEM or the tuner, and match the transmission ceiling accordingly.
Frequently Asked Questions
Are the gear ratios identical on both transmissions?
Yes. Both the RTLO16713A and RTLO16913A share the same gear ratio spread, including an identical 0.73:1 top overdrive gear. Fuel economy is effectively the same between models.
How long do these transmissions last?
With correct fluid maintenance and operation within their rated torque limits, both models routinely exceed 500,000 miles. The 16913A may last longer in applications where it is regularly loaded near its rated ceiling, thanks to heavier internal components.
Does the 16913A cost significantly more?
The price difference exists but is not dramatic. The 16913A commands a slightly higher purchase price and generally holds better resale value due to its higher torque rating. Over the life of the truck, the difference is often negligible compared to the cost of rebuilding a mismatched transmission.
Can I convert a 13-speed RTLO to an 18-speed?
No. As confirmed by the Eaton Fuller community, a 13-speed cannot be converted to an 18-speed by simply changing the shift knob. They are fundamentally different transmissions. You can convert an 18-speed to a 13-speed configuration by changing the shift handle — but not the other direction.
What oil should I use?
Eaton Fuller recommends 50W synthetic for optimal performance. If you're using mineral oil, 80W is the alternative recommendation. Synthetic is the better long-term choice for high-mileage applications.
Final Verdict
The RTLO16713A and RTLO16913A are both excellent transmissions from a company with a decades-long track record in heavy hauling. Choosing between them isn't about which one is "better" in some abstract sense — it's about matching the tool to the job.
The 16713A covers the majority of standard trucking applications brilliantly. The 16913A exists for the specific situations where 200 extra pound-feet of torque capacity makes a meaningful difference to component longevity and operational safety.
Know your engine's output. Know your load profile. Match accordingly. It really is that simple — and now you have the information to do it properly.
Sources & References
- Eaton Corporation — Fuller 13-Speed RTLO Series Specification Sheet
- TruckersReport.com — HP Ratings for RTLO16913A (Community Discussion)
- TruckersReport.com — Transmission Ratio Differences — A, B, C Types
- Pro Gear and Transmission — RTLO16713A Eaton Fuller Transmission Listing
- General Truck Parts — Fuller RTLO18913A Specs Overview
- Fleet Owner Magazine — High-Torque Transmissions from Eaton
- Eaton Fuller Transmission Guide 2015 — Full Specification Guide (PDF)
