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 SS 755 - WST 2023 X Series Odometer Reading Incorr...

SS 755 - WST 2023 X Series Odometer Reading
Incorrect With Split Shaft PTO's 
Applicable Vehicles
47X & 49X with split shaft PTO applications, Detroit Diesel engine & CEEA+ electrical architecture
2023 and prior.

Symptoms
Incorrect odometer readings with split shaft PTO is in operation.

Issue
On trucks with a Split Shaft PTO, the transmission output drive shaft rotates when the PTO is in
use. When the truck is stationary (not driving), this is shown as a road speed on the speedometer
and accumulates miles on the odometer, which is incorrect since the rear axle(s) are disconnected
so the vehicle is not moving. This is not desirable as it can use up the customer’s factory warranty,
incur road taxes, and cause error indications since the ABS sensors show correctly that the truck is
not moving.

Solution
Also, see alternate service solution SS750 for non tone ring revision.
The Detroit proprietary sensor will be used with a tone wheel installed after the SSPTO Transfer
case so that when the driveline to the rear axles is disconnected the CPC will see zero vehicle
speed even though the transmission output shaft is spinning to drive the PTO.

Installation
Factory wiring will be reconfigured and additional wiring and components will be added by the
Truck Equipment Manufacturer as follows. Sourcing and installation of the hardware, wiring, and
parameter changes will vary based upon the Transmission and SSPTO Transfer Case Brands that
are currently or will be installed in the truck.

Hardware
Acquire and install a Tone Wheel and Speed Sensor Mounting Bracket on the axle side of the SSPTO
Transfer Case.
NAMCOTM Transfer Cases
Driveline tone rings and Detroit sensor mounting brackets for several models of NAMCOTM transfer
cases are available. Contact NAMCOTM directly to confirm availability of parts for your specific
model. On some models an adapter collar is also required to mount the tone ring.
All other models
First, contact your transfer case manufacturer to determine if a tone wheel and sensor mounting
bracket specific to the DetroitTM sensor are available. If no manufacturer solution is available this ,
a Tone wheel must be locally designed and sourced. The following is an example for use in
developing your custom design.
Note 1: The picture below is for a 14-hole design. We recommend creating a 16-hole design since
that is the default programmed number in the CPC5 software.
Note 2: The center hole pattern needs to be designed to match the driveline mounting bolts on the
flange or yolk of the transfer case.
Note 3: A single piece tone wheel is preferred, but if your transfer case will require disassembly to
install a single piece, a split tone wheel such as the one shown below is a better solution.

Example of a complete installed Tone Wheel is shown here:

Speed sensor mounting bracket requirements.

Speed Sensor

Sensor Alignment
The center of the sensor must align with the center of the hole in the tone wheel during rotation.

The sensor must not come in contact with the tone wheel.
The face of the sensor must be parallel to the face of the tone wheel.
The sensor gap must be maintained throughout the rotation of the tone wheel at 0.050 inches +/0.010 inches.

Wiring
Complete the wiring modifications and installation as follows.

Eaton Manual & Automated Manual
Factory sensor and wiring will need to be extended to the new location on the Tone Wheel mounted
to the driveline on the output of the SSPTO Transfer case.

Allison Transmission
The wiring to the vehicle speed sensor that is factory installed on the tailshaft housing will be
modified by installing a relay and an additional speed sensor mounted under the dash.
Create a new wiring harness as shown below with enough length to reach from the new speed
sensor location to the CPC5 in the dash.

Programming
For the Eaton manual transmission no change to the CPC5 programming is required, but with an
Allison transmission, the CPC5 is factory programmed to read the J1939 speed signal from the
Allison TCM. The CPC must be reconfigured to use a wired sensor signal.
For these instructions, speed sensing is configured like a manual transmission. The speed signal is
routed to the CPC to make calculations to determine vehicle speed when the vehicle is moving.
When the vehicle is stationary the speed signal will show zero since the driveline to the rear axles
will not be rotating.
Verify parameters in CPC5 are set as follows using DetroitTM Diagnostic Link software
configuration tool:
1. Axle Ratio
1. 233-Powertrain Configuration Axle Ratio
1. Rear Axle Ratio 1 of 2
Verify axle ratio is set
2. Rear Axle Ratio 2 of 2
Verify axle ratio is set
2. Vehicle Speed Sensor
1. 330 – Vehicle Speed Sensor
1. Tire Revs per unit distance
Set to value for the tires
2. Vehicle Speed Sensor =
OutputshaftSpeed hall sensor
average
2. Teeth per gear
1. 11 – Vehicle Configuration
1. cdi_pVehConf.TissTeethNum_u8 =
Number of holes on the
tone wheel
If your tone wheel has 16 teeth, setting this parameter is not necessary since this is the default
setting in the CPC5. If your tone wheel has a different number of holes, a call to the Detroit
Customer Assistance Center is required in order to complete this step.
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47X

49X

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