RTO16915-P | RTX16915-P | Eaton Fuller Roadranger | 15 Speed Transmission | DPX Reman

RTO16915-P / RTX16915-P / RTOF16915 / RTXF16915 | Eaton Fuller Roadranger 15-Speed Transmission — Remanufactured by DPX (Design Level 9)

The RTO16915-P / RTX16915-P / RTOF16915 / RTXF16915 is a heavy-duty Eaton Fuller Roadranger 15-Speed transmission (Design Level 9) with a manual 5-speed front section and air-shifted auxiliary section. Features the signature 2.794"-54 spline output shaft and internal oil pump. Remanufactured in Mansfield, Ohio by Discount Parts Exchange - DPX. Every unit is completely torn down, cleaned, inspected, and rebuilt to factory specifications with new bearings, seals, synchros, and air components.

Call DPX to confirm: 419-522-3320.

Highlights

• Model: RTO16915-P / RTX16915-P / RTOF16915 / RTXF16915 — 15-Speed (Design Level 9)
• Configuration: Manual 5-speed front section + air-shifted auxiliary section
• Max Torque: 1,650 lb-ft
• Output Shaft: 2.794" - 54 spline
• Input Shaft: S-1659 – 2.00" 10 spline
• Internal Oil Pump: Yes
• Oil Capacity: 28 pints
• Weight: 696 lb
• Length: 33.1 inches
• Common Applications: Kenworth, Peterbilt, Volvo, Mack, Freightliner, International, Western Star, and other heavy-duty Class 8 trucks

Design Level 9 vs Design Level 7 – Key Differences

The number that follows the torque rating in the Eaton Fuller model designation indicates the Design Level:

• RTO15715 series = Design Level 7
• RTO16915 series = Design Level 9

Design Level 9 features the improved seal system and a larger output shaft. Here is the practical difference for parts and identification:

Always verify the output shaft spline count and the Design Level number in the model designation before ordering seals, nuts, or yokes.

Gear Ratios – Eaton Fuller 15-Speed (RTO/RTX 16915 Series)

Overall Reduction: 16.94 • Low-Low: 13.14 • Low: 7.73 • High: 2.17

Understanding How a 15-Speed Transmission Works

Many drivers and technicians look at the shift pattern and wonder: “Why does a 15-speed only show five positions?” The answer is simple once you understand how the air system multiplies those five main gears.

The RTO16915-P / RTX16915-P is built around a standard 5-speed front box (main gearbox). The remaining 10 speeds come from the air-shifted auxiliary section (back box) that sits behind the main box. That auxiliary section has two air-controlled functions:

• Range Selector — switches the entire back box between Low range and High range
• Splitter Button — splits each main gear into a Low and High step (or Direct and Overdrive)

When you combine the 5 main gears with the Range and Splitter, you get the full 15 forward speeds (plus reverse). The shift pattern plate only shows the five lever positions because the Range and Splitter are controlled by the air switches on the shift knob.

Here’s how it works in the seat:

• You shift the stick through the five main gears exactly like a regular 5-speed
• You pre-select Range (Low or High) with the range lever or switch before you move the stick
• You use the splitter button on the shift knob for half-steps within each gear (especially useful in 5th–8th)

Once you understand that the stick only selects the main gear and the air system multiplies it, the 15-speed becomes very straightforward to operate. Proper air supply and a correctly functioning A5000 range valve (included on every DPX reman unit) are critical for smooth range and splitter shifts.

What’s Included

• Remanufactured Eaton Fuller 15-Speed Roadranger transmission rebuilt to factory spec by Discount Parts Exchange - DPX
• New A5000 range valve, air hoses, and A5454/K2170 air filter regulator
• 12-month, unlimited-mileage parts-only warranty
• Tech support from DPX during installation and break-in

Critical Specs & Common Service Parts

K-2918 Output Seal Kit Contents

Tech Tip – Critical Output Seal & Bearing Cover Installation

There are two gasket options for the rear bearing cover that are seal-retainer specific and must be matched correctly.

Most important: When installing the rear bearing cover, make sure that one of the notches in the face of the housing aligns with the oil port on the mating surface of the plate.

Failure to align the oil port hole will starve the output bearing of oil, resulting in a burnt output bearing pack and premature transmission failure.

Related Products

DPX Drivetrain Tools Hub

Free tools built by rebuilders for mechanics, drivers, and fleets:

Road Speed Calculator • Gear Ratio Charts • PTO Shimming Guide • Full IPL Library →

DPX — Ohio’s Premier Heavy-Duty Drivetrain Rebuilder | Built to Perform. Trusted to Last.